Program

June 18-21 2009
Oslo, Norway
Bridging the gap between theory and experiment
Program and abstracts
CTCC
Hotel Vettre, Asker
Molecular Properties ’09
Molecular
Properties
'09
bridging
the
gap
between
theory
and
experiment
an
ICQC
2009
satellite
symposium
June
18–21
2009
Thon
Hotel
Vettre,
Vettre,
Norway
Organizing
Committee
Trygve
Helgaker
(chair),
Bogumil
Jeziorski,
Peter
J.
Knowles,
Kenneth
Ruud
Secretaries
John
McNicol
and
John
Vedde
Technical
Assistant
Vladimir
Rybkin
Sponsors
Research
Council
of
Norway
(RCN)
Centre
for
Theoretical
and
Computational
Chemistry
(CTCC)
1
Molecular Properties ’09
2
Molecular Properties ’09
Dear
participant
of
MP09,
The
organizing
committee
has
great
pleasure
in
welcoming
you
to
Norway
for
Molecular
Properties
'09,
an
ICQC
2009
satellite
symposium
devoted
to
the
calculation
of
molecular
properties
by
quantum‐chemical
methods,
including
developments
in
methodology
and
applications
to
challenging
problems
in
chemistry
and
physics,
with
emphasis
on
the
relationship
between
theory
and
experiment.
At
MP09,
you
will
hear
about
the
latest
developments
in
the
theory
and
calculation
of
molecular
properties
from
some
of
the
foremost
workers
in
the
field;
during
the
next
three
days,
117
participants
from
21
countries
will
give
a
total
of
35
oral
presentations
and
54
poster
presentations.
It
is
our
hope
that
these
presentations
and
our
discussions
will
stimulate
us
all
towards
new
directions
and
developments
in
this
field.
The
MP09
symposium
is
sponsored
by
the
Research
Council
of
Norway
(RCN)
and
by
the
Centre
for
Theoretical
and
Computational
Chemistry
(CTCC),
a
Centre
of
Excellence
established
by
the
RCN
in
2007
and
shared
between
the
University
of
Oslo
and
the
University
of
Tromsø.
We
invite
you
to
visit
our
home
page
http://www.ctcc.no/
or,
even
better,
to
visit
our
research
groups
for
a
shorter
or
longer
period,
noting
that
the
CTCC
has
an
extensive
program
for
visiting
scholars.
Trygve
Helgaker,
Bogumil
Jeziorski,
Peter
J.
Knowles,
and
Kenneth
Ruud
Organizing
committee
of
MP09
3
Molecular Properties ’09
4
Molecular Properties ’09
13:00
Registration
opens
16:00
Opening
T.
Helgaker
Chair:
E.
Eliav
Session
I:
Excited
states
(L1–L4)
16:10
W.
Domcke:
Vibronic coupling by the spin-orbit operator in molecules and clusters
16:50
C.
M.
Marian:
Spin-dependent properties of electronically excited organic molecules
17:15
M.
S.
Deleuze:
Probing excited states and nuclear dynamics in momentum space
17:40
S.
Evangelisti:
Edge states and singlet-triplet degeneracy in linear atomic chains
18:05
Coffee
Session
II:
Spectroscopy
(L5–L7)
Chair:
C.
Puzzarini
18:25
J.
Gauss:
Interplay of theory and experiment in rotational spectroscopy
19:05
B.
Kirtman: Computational methods for evaluating the vibrational
contribution to electronic properties
19:45
G.
Rauhut:
Towards an efficient calculation of anharmonic vibrational spectra
20:10
Barbecue
dinner
5
Molecular Properties ’09
MP09
Friday
June
19
07:30
Breakfast
Session
III:
Large
systems
I
(L8­L10)
Chair:
P.
J.
Knowles
08:45
P.
Jørgensen:
Three level optimization of the Hartree–Fock/Kohn–Sham energy for
reliable convergence to an optimized energy and for generating localized molecular
orbitals both for the occupied and virtual orbital spaces
09:25
M.
Olivucci:
From computational photobiology to the design of an ultrafast
biomimetic molecular switch
10:05
H.
Nakai:
Divide-and-conquer linear-scaling calculation for polarizability
10:30
Coffee
Session
IV:
Large
systems
II
(L11–L13)
Chair:
S.
Coriani
11:00
L.
Visscher:
Calculation of local molecular properties using a subsystem density
functional approach
11:40
C.
Ochsenfeld:
Linear-scaling calculation of molecular properties for large
molecules
12:05
F.
Aquilante:
Cholesky decomposition-based ab initio density fitting: locality
from completeness
12:30
Lunch
Session
V:
Electron
correlation
I
(L14–L16)
Chair:
B.
Jeziorski
14:00
W.
Klopper:
Explicitly correlated molecular electronic wave functions: Energies and
analytic derivatives
14:40
H.‐J.
Werner:
Accurate calculation of molecular properties using explicitly
correlated coupled cluster methods
15:20
B.
Hajgato: A determination of the ionization energies, electron affinities and singlettriplet energy gaps of benzene and linear acenes within chemical accuracy
15:45
Coffee
Session
VI:
Electron
correlation
II
(L17–L19]
Chair:
D.
Mukherjee
16:15
T.
Yanai: Canonical transformation theory for large-scale multireference
electronic structure calculations
16:55
M.
R.
Hoffmann:
Molecular properties for second-order generalized Van Vleck
perturbation theory
17:20
M.
Nooijen:
On a manifestly covariant many-body theory or tinkering with the
laws of physics
18:30
Fjord
cruise
6
Molecular Properties ’09
MP09
Saturday
June
20
07:30
Breakfast
Session
VII:
Intermolecular
interactions
(L20­L22)
Chair:
H.
P.
Lüthi
08:45
K.
Szalewicz:
Connection
between
molecular
properties
and
intermolecular
interaction
potentials
09:25
T.
Korona:
Coupled
cluster
treatment
of
intramonomer
correlation
effects
in
symmetry­adapted
perturbation
theory
10:05
R.
J.
Wheatley:
Atomic
charge
densities
and
polarizabilities
10:30
Coffee
Session
VIII:
Adiabatic
and
nonadiabatic
effects
(L23–L24)
Chair:
K.
Ruud
11:00
E.
F.
Valeev:
Is
the
adiabatic
approximation
sufficient
to
account
for
the
post­
Born­Oppenheimer
effects
on
molecular
electric
dipole
moments?
11:40
J.
Komasa:
Perturbative
theory
of
nonadiabatic
effects
in
molecules
12:30
Lunch
Session
IX:
Density­functional
theory
(L25–L28)
Chair:
W.
Liu
14:00
D.
J.
Tozer:
Excited
states
from
TDDFT:
Predicting
failures
and
improving
accuracy
14:40
T.
Van
Voorhis:
Exploring
electron
transfer
and
bond
breaking
with
constrained
DFT
15:20
N.
A.
Besley:
Time
dependent
density
functional
theory
calculations
of
near­edge
X­ray
absorption
fine
structure
15:45
D.
R.
Rohr:
Treatment
of
correlation
in
density
matrix
functional
theory
16:45
Poster
Session
19:30
Banquet
dinner
7
Molecular Properties ’09
MP09
Sunday
June
21
07:30
Breakfast
Session
X:
Magnetic
properties
(L29–L32)
Chair:
G.
A.
Aucar
08:45
K.
Pachucki:
Relativistic, QED, and finite nuclear mass effects in the theory of
magnetic properties
09:25
M.
Jaszunski:
NMR spectra bypassing the chemical shift
09:50
K.
Yamaguchi:
Ab initio calculations of magnetic interaction parameters in
molecules-based materials
10:15
A.
V.
Arbuznikov:
Local hybrid functionals: Implementation and validation of
coupled-perturbed Kohn–Sham calculations of EPR parameters
10:40
Coffee
Session
XI:
Optical
properties
and
activity
(L33–L35)
Chair:
D.
Crawford
11:00
F.
Furche:
Optimized Gaussian basis sets for molecular optical property calculations
11:40
M.
Pecul:
Optical activity of β,γ-enones in ground and excited state
12:05
C.
R.
Jacob:
Understanding the Raman optical activity spectra of polypeptides with
localized vibrations
12:30
Closing
12:35
Lunch
8
P.
J.
Knowles
Molecular Properties ’09
Speakers
in
alphabetical
order
with
references
to
abstracts:
Aquilante
[L13]: Cholesky decomposition-based ab initio density fitting: locality
from completeness
Arbuznikov
[L32]: Local hybrid functionals: Implementation and validation of
coupled-perturbed Kohn-Sham calculations of EPR parameters
Besley
[L27]: Time
dependent
density
functional
theory
calculations
of
near­
edge
X­ray
absorption
fine
structure
Deleuze
[L03]: Probing excited states and nuclear dynamics in momentum space
Domcke
[L01]: Vibronic coupling by the spin-orbit operator in molecules and
clusters
Evangelisti
[L04]: Edge states and singlet-triplet degeneracy in linear atomic chains
Furche
[L33]: Optimized Gaussian basis sets for molecular optical property
calculations
Gauss
[L05]: Interplay of theory and experiment in rotational spectroscopy
Hajgato
[L16]: A determination of the ionization energies, electron affinities and
singlet-triplet energy gaps of benzene and linear acenes within
chemical accuracy
Hoffmann
[L18]: Molecular properties for second-order generalized Van Vleck
perturbation theory
Jacob
[L35]: Understanding the Raman optical activity spectra of polypeptides
with localized vibrations
Jaszunski
[L30]: NMR spectra bypassing the chemical shift
Jørgensen
[L08]: Three level optimization of the Hartree–Fock/Kohn–Sham energy
for reliable convergence to an optimized energy and for generating
localized molecular orbitals both for the occupied and virtual
orbital spaces
Kirtman
[L06]: Computational methods for evaluating the vibrational contribution
to electronic properties
Klopper
[L14]: Explicitly correlated molecular electronic wave functions: Energies
and analytic derivatives
Komasa
[L24]: Perturbative
theory
of
nonadiabatic
effects
in
molecules
Korona
[L21]: Coupled cluster treatment of intramonomer correlation effects in
symmetry-adapted perturbation theory
Marian
[L02]: Spin-dependent properties of electronically excited organic
molecules
Nakai
[L10]: Divide-and-conquer linear-scaling calculation for polarizability
Nooijen
[L19]: On a manifestly covariant many-body theory or tinkering with the
laws of physics
9
Molecular Properties ’09
Ochsenfeld
[L12]: Linear-scaling calculation of molecular properties for large
molecules
Olivucci
[L09]: From computational photobiology to the design of an ultrafast
biomimetic molecular switch
Pachucki
[L29]: Relativistic, QED, and finite nuclear mass effects in the theory of
magnetic properties
Pecul
[L34]: Optical activity of β,γ-enones in ground and excited state
Rauhut
[L07]: Towards an efficient calculation of anharmonic vibrational spectra
Rohr
[L28]: Treatment
of
correlation
in
density
matrix
functional
theory
Szalewicz
[L20]: Connection between molecular properties and intermolecular
interaction potentials
Tozer
[L25]: Excited states from TDDFT: Predicting failures and improving
accuracy
Valeev
[L23]: Is the adiabatic approximation sufficient to account for the postBorn-Oppenheimer effects on molecular electric dipole moments?
Van Voorhis
[L26]: Exploring electron transfer and bond breaking with constrained
DFT
Visscher
[L11]: Calculation of local molecular properties using a subsystem density
functional approach
Werner
[L15]: Accurate calculation of molecular properties using explicitly
correlated coupled cluster methods
Wheatley
[L22]: Atomic charge densities and polarizabilities
Yanai
[L17]: Canonical transformation theory for large-scale multireference
electronic structure calculations
Yamaguchi
[L31]: Ab initio calculations of magnetic interaction parameters in
molecules-based materials
10
Molecular Properties ’09
Poster
presenters
in
alphabetical
order
with
references
to
abstracts:
Aucar
[P01]: Polarization propagators: a powerful tool for both reliable
calculations and the analysis of NMR spectroscopic parameters on
heavy and non-heavy atom containing molecules
Bast
[P02]: Implementation of high-order response functions with exchangecorrelation contribution and relativity
Belpassi
[P03]: Chemical characterization of superheavy elements on gold clusters
by 4-component full relativistic DFT
Bernstein
[P04]: Molecular dynamics simulations of Cs+@C60 impact formation
Borini
[P05]: The COSTMAP initiative: data mining of molecular information
from a graph-based database
Borrelli
[P06]: The photoelectron spectrum of ammonia, a test case for the
calculation of Franck-Condon factors in molecules undergoing
large geometrical displacements upon photoionization
Cheng
[P07]: Four-component relativistic theory for NMR parameters
Coriani
[P08]: In silico determination of optical and spectroscopic properties: a
few recent methodological and applicative results
Crawford
[P09]: First-principles studies of optical rotation and circular dichroism
spectra
Cukras
[P10]: The second-order magnetic and electric properties of RgH+ cations
Eliav
[P11]: Benchmark calculations of the nuclear quadrupole moments in
heavy atomic systems
Escudero
[P12]: Photochemical properties of Ir and Pt organometallic complexes
Ferre
[P13]: A QM/MM//MD model for the computation of aqueous nitroxide
hyperfine coupling constants
Gao
[P14]: High order properties by solving equation of motion of first order
reduced density matrix in Hartree-Fock or density functional theory
using perturbation- and time-dependent basis sets
Gonzalez-Garcia [P15]: Theoretical investigation of new nucleation precursors in the
atmospheric SO2 oxidation
Grisanti
[P16]: Essential state models for functional molecular material:
crossing the line between theory and experiment
Guo
[P17]: EVV 2DIR spectroscopy: determination of intermolecular geometry
via electrical anharmonic couplings
Hachmann
[P18]: Formal oxidation states and realistic charge distributions in
transition metal chemistry
Harding
[P19]: Atomic natural orbital basis sets from coupled-cluster wave
functions
Höfener
[P20]: Relaxed RI-MP2-F12 first-order properties
11
Molecular Properties ’09
Iwata
[P21]: Deuteration effects on the enthalpy and entropy changes in
encapsulation of methyl-containing guest molecules in molecular
cages: Importance of the increase of internal rotation barrier
Janecek
[P22]: Any-order imaginary time propagators for solving Schrödinger
equations
[P23]: Manifestly gauge covariant density functional theory calculations in
strong magnetic fields
12
Janssens
[P24]: Information theoretical study of the chirality of enantiomers
Jonsson
[P25]: Excited state polarizabilities
Kelterer
[P26]: TD-DFT calculations on the photophysics in Eu-complexes
Kjærgård
[P27]: A modified preconditioned conjugated gradient method for the
computation of singular linear response equations
Kolar
[P28]: Accurate determination of the structure of non-covalent phenol
complexes
Kristensen
[P29]: Quasienergy formulation of damped response theory
Kubar
[P30]: Charge transfer in DNA: effect of dynamics and environment
Kurtz
[P31]: Effective core potential basis sets for polarizability and
hyperpolarizabilities
Liakos
[P32]: Analysis of the zero-field splitting in Cr(H2O)62+ through multiconfigurational ab initio calculations
Liu
[P33]: Exact two-component Hamiltonians Revisited
Lüthi
[P34]: Relating molecular properties to chemical concepts: electron
delocalization in linearly π-conjugated compounds and the
properties of donor/acceptor functionalized polyacetylenes
Mao
[P35]: A spin-adapted size-extensive state-specific multi-reference
perturbation theory (SS-MRPT) for energy and electrical properties
Monaco
[P36]: On the additivity of current density in polycyclic conjugated
hydrocarbons
Monari
[P37]: Mixed-valence behavior in phtalocyanine-dimer cations
Mori
[P38]: Recent developments and applications of relativistic model core
potentials for 1st-3rd transition metal elements
Neuscamman
[P39]: Preliminary investigation of free base porphin using the full 24
orbital valence space
Olejniczak
[P40]: NMR properties of heavy­metal complexes
Peluso
[P41]: The charge transfer band of oxidized Watson-Crick guanosinecytidine complex
Pennanen
[P42]: Theory of paramagnetic NMR chemical shift in the presence of
zero-field splitting
Molecular Properties ’09
Puzzarini
[P43]: A new absolute 17O NMR scale: rotational spectroscopy and
quantum chemical calculation
Respondek
[P44]: Anharmonic vibrational calculations and the IET spectrum of an
adsorbed species on a metal surface
Rozyczko
[P45]: Correlated corrections for semiempirical methods. Ground and
excited states
Rulisek
[P46]: Effect of spin-orbit coupling on reduction potentials of octahedral
ruthenium (II/III) and osmium (II/III) complexes
Sagvolden
[P47]: The (2-pyridone)2 dimer and some observations about excitation
energy transfer
Solheim
[P48]: Complex polarization propagator calculations of magnetic circular
dichroism spectra
Srnec
[P49]: Reaction mechanism of stearoyl-ACP Δ9-desaturase (Δ9D):
combined computational and spectroscopic study
Steindal
[P50]: Linear response QM/MM/PCM: Theory and applications
Teale
[P51]: Benchmarking density-functional-theory calculations of rotational g
tensors and magnetizabilities using accurate coupled-cluster
calculations
Woywod
[P52]: Theoretical investigation of the electronic spectrum of pyrazine
Yachmenev
[P53]: An efficient approach for calculating rotation-vibration and
temperature corrections to molecular properties
Yousaf
[P54]: Combining screened hybrid density functionals with empirical
dispersion corrections for extended systems
13
Abstracts
of
Lectures
Molecular Properties ’09 - Lectures
Vibronic coupling by the spin-orbit operator in molecules and clusters
Wolfgang Domcke1 and Leonid V. Poluyanov2
1) Department of Chemistry, Technical University of Munich, Germany
2) Institute of Chemical Physics, Academy of Sciences, Chernogolovka, Russia
Vibronic coupling is a time-honored and widely known concept in the electronic spectroscopy
of polyatomic molecules [1]. The basic ingredients are diabatic electronic basis states, the
Taylor expansion of the nonrelativistic Hamiltonian in nuclear normal coordinates at a
suitable reference geometry, as well as the use of symmetry selection rules. In this talk, the
systematic extension of these concepts to spin-orbit (SO) coupling effects is discussed,
employing the microscopic Breit-Pauli SO operator [2]. The fundamental symmetry
properties of the Breit-Pauli operator are analyzed for the example of a single unpaired
electron in a triangular system (D3h symmetry) as well as for the tetrahedron (Td symmetry).
The Jahn-Teller (JT) Hamiltonians of 2E states as well as of E states of higher spin
multiplicity ( 3E, 4E, etc.) in trigonal systems are discussed [3]. As another example, it is
shown that a purely relativistic first-order ExT JT effect exists in 2E states of tetrahedral
systems [4]. In 2Π and 3Π states of linear molecules, the microscopic SO operator gives rise
to vibronic coupling terms which are of first order in the bending mode [5, 6]. The latter
results resolve long-standing problems in the analysis of the vibronic structures of 2Π states
in linear triatomic molecules (Renner effect) [6].
References:
1. I. B. Bersuker, The Jahn-Teller Effect, Cambridge UP, Cambridge, 2007.
2. H. A. Bethe, E. E. Salpeter, Quantum Mechanics for One- and Two-Electron Atoms,
Springer, Berlin, 1957.
3. L. V. Poluyanov and W. Domcke, Chem. Phys. 352, 125 (2008).
4. L. V. Poluyanov and W. Domcke, J. Chem. Phys. 129, 224102 (2008).
5. S. Mishra, V. Vallet, L. V. Poluyanov and W. Domcke, J. Chem. Phys. 123, 124104
(2005).
6. S. Mishra, L. V. Poluyanov and W. Domcke, J. Chem. Phys. 126, 134312 (2007).
L1
Molecular Properties ’09 - Lectures
Spin-Dependent Properties of Electronically Excited Organic
Molecules
Christel M. Marian
Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf,
Universitätsstraße 1/26.32, 40225 Düsseldorf, Germany
E-mail: [email protected]
In recent years a toolbox for the determination of spin-dependent properties, such as
zero-field splittings, g-tensors, phosphorescence and intersystem crossing rates, has been
developed in our laboratory.[1−4] The methods are based on the combined density functional and multi-reference configuration interaction approach (DFT/MRCI) for a spin-free
Hamiltonian.[5] For the evaluation of first-order properties, spin-orbit and spin-spin coupling are included as a perturbation while higher-order properties are preferentially determined employing multi-reference spin-orbit configuration interaction (MRSOCI) wave
functions.
By means of the above mentioned methods, we have investigated the electronic spectra
and spin-dependent properties of a variety of biologically relevant chromophores such as
porphyrins, flavins, flavones, and DNA bases. The methods will be briefly introduced and
a few representative cases will be presented.
References
[1] (a) M. Kleinschmidt, J. Tatchen, C. M. Marian, J. Comp. Chem. 23 (2002) 824.
(b) M. Kleinschmidt, C. M. Marian, Chem. Phys. 311 (2005) 71.
(c) M. Kleinschmidt, J. Tatchen, C. M. Marian, J. Chem. Phys. 124 (2006) 124101.
[2] (a) J. Tatchen, C. M. Marian, Phys. Chem. Chem. Phys. 8 (2006) 2133.
(b) J. Tatchen, N. Gilka, C. M. Marian, Phys. Chem. Chem. Phys. 9 (2007) 5209.
[3] N. Gilka, P. R. Taylor, C. M. Marian, J. Chem. Phys. 129 (2008) 044102.
[4] J. Tatchen, M. Kleinschmidt, C. M. Marian, J. Chem. Phys. 130 (2009) 154106.
[5] S. Grimme, M. Waletzke, J. Chem. Phys. 111 (1999) 5645.
L2
Molecular Properties ’09 - Lectures
Probing Excited States and Nuclear Dynamics in Momentum Space
M.S. Deleuze
Theoretical Chemistry, Department SBG, Hasselt University, Agoralaan Gebouw D,
B-3590 Diepenbeek, Belgium
Electron Momentum Spectroscopy (EMS) is a powerful “orbital imaging” technique, which enables
direct experimental reconstructions of one-electron transition momentum densities associated to specific
ionization channels. The Born, electron binary encounter, weak coupling and plane wave impulse
approximations are usually invoked, and justify the mapping of experimental momentum distributions
inferred from an angular analysis of vertical (e,2e) electron impact ionization intensities at specific
electron binding energies onto Dyson orbital momentum distributions. In most applications of the
theory, (normalized) Dyson orbitals are replaced by standard Kohn-Sham orbitals. A first complication
in the interpretation of EMS experiments often takes the form of a dispersion of the ionization intensity
over electronically excited (shake-up) configurations of the cation. When the molecular target contains
rotatable bonds, another difficulty pertains to the usually very strong influence of the molecular
conformation onto electron binding energies. Ultra-fast nuclear dynamics in the final state may also lead
to significant fingerprints into the observed momentum distributions. At last, when the plane wave
impulse approximation breaks down, the (e,2e) ionization cross sections relate to mathematical
transforms involving distorted waves. The purpose of the present contribution is to illustrate how a
proper treatment of these complications can be used for probing in momentum space the consequences
of electron correlation and nuclear dynamics in neutral and cationic states.
An extensive study of the (e,2e) valence ionization spectra and related electron momentum
distributions is therefore presented, in order to interpret high resolution EMS experiments onto two
conformationally versatile but structurally very opposite molecules, namely 1,3-butadiene [1] and
ethanol [2]. The analysis is based on calculations of valence one-electron and shake-up ionization
energies and of the related Dyson orbitals, using one-particle Green’s Function (1p-GF) theory in
conjunction with the so-called third-order Algebraic Diagrammatic Construction scheme [ADC(3)].
Thermally and spherically averaged electron momentum distributions are correspondingly computed
from Dyson orbitals, using conformer weights derived from other experiments or thermostatistical
calculations that account for the influence of hindered rotations. In agreement with thermodynamics, the
ionization spectra and Dyson orbital momentum distributions of 1,3-butadiene demonstrate that the
gauche structure is totally incompatible with ionization experiments in high vacuum and at standard
temperatures. On the other hand, the analysis of the angular dependence of (e, 2e) ionization intensities
confirms the presence of an intense π-2 π*+1 shake-up satellite at an electron binding energy of ~13.1 eV.
In very sharp contrast with π-conjugated molecules, the one-electron picture of ionization holds up to
~24 eV for ethanol. Despite the high order attained in the treatment of electron correlation and
relaxation, a first ADC(3) analysis that accounts for energy minima only fails in quantitatively
reproducing the experimental momentum distribution characterizing the HOMO. The extremely limited
dependence of the momentum distributions onto the energy of the impinging electron rules out the
possibility of a breakdown of the plane wave impulse approximation. Thermal averaging of the
outermost momentum distribution over a set of 1728 model structures on the potential energy surface of
ethanol in its neutral ground state and further DFT calculations for the radical cation employing Born
Oppenheimer Molecular Dynamics indicate that the discrepancy between theory and experiment reflects
strong deviations from a vertical picture of ionization, in the form of a stretching of the C-C bond by
~0.25 Å, and a shortening of the C-O bond by ~0.10 Å, within timescales of the order of ~13 fs. This
ultra-fast reorganization of the molecular structure induces in turn a delocalization of the outermost
oxygen lone pair onto the C-C bond, and a very strong enhancement of the momentum distribution
characterizing the HOMO at low electron momenta. This enhancement images in momentum space the
charge transfer that occurs through this orbital during the very first stages of the dissociation of the
ethanol radical cation into a methyl radical and a protonated form of formadelhyde.
[1] M. S. Deleuze, S. Knippenberg, J. Chem. Phys. 125, 104309 (2006)
[2] F. Morini, B. Hajgató, M. S. Deleuze, C. G. Ning, J. K. Deng, J. Phys. Chem. A, 112, 9083 (2008).
[3] B. Hajgató, M. S. Deleuze, F. Morini, accepted for publication in J. Phys. Chem. A
L3
Molecular Properties ’09 - Lectures
Edge States and Singlet-Triplet
Degeneracy in Linear Atomic Chains
Stefano Evangelisti, Thierry Leininger,
Laboratoire de Chimie et Physique Quantiques,
Université de Toulouse et CNRS, Toulouse - France
Antonio Monari, Gian Luigi Bendazzoli
Dipartimento di Chimica Fisica e Inorganica,
Università di Bologna, Bologna -Italy
Beryllium linear chains present two quasi-degenerated edge orbitals located
at the chain extremities. This represents a nice illustration of the surface states
predicted by Tamm and Shockley long ago. The presence of these edge orbitals
has several interesting consequences:
• The two quasi-degenerated orbitals, one above and one below the Fermi
level, globally host two electrons. This produces one singlet and one triplet
quasi-degenerated states, whose splitting quickly decreases with the increasing of the chain length.
• The existence of ionic low-lying states is also expected. Therefore, the
properties of the system in presence of magnetic or electric fields are worth
to be investigated, as well as the effect of the Spin-Orbit coupling on these
states.
• Positive or negative ions can be obtained by extracting or adding one
electron to the system. Because of geometry distortion, the charge will
localize in one of the edge orbitals, and give rise, in the case of sufficiently
long chains, to bistable systems.
Our calculation show that this behavior is a general one, shared by all the
alkaly-earth elements of Group 2. From a methodological point of view, these
systems represent a very stringent test for different approximated methods (like
Configuration Interaction, Coupled Cluster, Perturbation Theory, etc.), because
of the difficulty of computing both the singlet-triplet splitting and the fragmentation energy. Experimentally, edifices showing these characteristics could be
realized by deposing these atoms on an inert surface. A further possibility
would be to host such atomic chains within a hollow structure, like for instance
a nanotube.
References
[1] A. Monari, V. Vetere, G.L. Bendazzoli, S. Evangelisti, and B. Paulus,
Chem. Phys. Lett., 465, 102-105 (2008).
[2] V. Vetere, A. Monari, A. Scemama, G.L. Bendazzoli, and S. Evangelisti, J.
Chem. Phys., 130, 024301 (2009).
[3] W. Helal, A. Monari, S. Evangelisti, and T. Leininger, J. Phys. Chem. A,
113, 5240-5245 (2009).
1
L4
Molecular Properties ’09 - Lectures
Interplay of Theory and Experiment in Rotational Spectroscopy
Jürgen Gauss
Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
It will be demonstrated how quantum-chemical calculations can be used to assist experimental investigations in the field of rotational spectroscopy. Examples will be given for
the detection of new molecules based on high-accuracy predictions of the corresponding spectroscopic parameters, the determination of molecular geometries using rotational
spectroscopy, the analysis of the hyperfine pattern in experimental spectra using computed values, and the determination of absolute NMR scales based on experimentally
determined nuclear spin-rotation constants.
L5
Molecular Properties ’09 - Lectures
Computational Methods for Evaluating the Vibrational Contribution
to Electronic Properties
Bernard Kirtman
Department of Chemistry and Biochemistry
University of California, Santa Barbara, CA. 93106-9510 USA
Electronic properties are often evaluated under the clamped nucleus approximation. However,
even for first-order properties (i.e. expectation values), there is always a zero-point vibrational
averaging (zpva) contribution due to nuclear motion. For higher-order properties, there are
additional contributions that arise from virtual vibrational excitations on the ground state
potential energy surface. Whereas the zpva term can be important, the latter contributions can
exceed the clamped nucleus value. Furthermore, since virtual excitations are involved, large
mechanical anharmonicity and highly non-linear dependence of the property on vibrational
displacements can play a major role. Using nonlinear optical properties as an example we will
present accurate computational methods that have recently been developed for this problem.
Specific topics that will be covered include: (1) relaxation vs. perturbation theory approach; (2)
vibrational wavefunctions for large amplitude motions; (3) reduced dimensionality treatment of
large molecules; and (4) application to other properties. Some future directions that require
further exploration will be noted.
L6
Molecular Properties ’09 - Lectures
Towards an Efficient Calculation of Anharmonic Vibrational Spectra
Guntram Rauhut
Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55,
70569 Stuttgart, Germany
The variational determination of vibrational wave functions beyond the harmonic approximation is hampered by two computational bottlenecks: (1) The calculation of an
accurate potential energy surface around the equilibrium structure and (2) the vibration
correlation calculation by means of post-VSCF methods. Remedies to both problems
will be presented which shift the application of these methods to molecules with more
than 10 atoms.
It is well-known that for the accurate calculation of vibrational transitions the expansion
of the potential in terms of many-mode contributions
X
X
X
Vijk (qi , qj , qk ) + . . .
(1)
V (q) =
Vi (qi ) +
Vij (qi , qj ) +
i
i<j
i<j<k
cannot be truncated after the 2D terms, but needs the explicit inclusion of high-order
terms. This increases the number of ab initio grid points tremendously. A modeling
scheme for the 3D terms will be presented which makes use of the underlying 1D and
2D contributions which can efficiently be determined by state-of-the-art CCSD(T)-F12a
calculations in combination with small basis sets. Mean absolute deviations due to the
modeling are in the range of about 2 cm−1 while a speed-up of about 3 orders of magnitude can be gained.
Vibration correlation effects can be accounted for by vibrational configuration interaction (VCI) methods. An efficient state-specific configuration-selective VCI approach
based on an iteratively refined VMP2-based selection criterion allows to process about
5 · 107 configurations, once the potential is represented by polynomials and truncated
after the 3D terms. This allows for the inclusion of quadruple-excitations within the VCI
program which were found to be nonnegligible for accurate calculations. Speed-ups by
several orders of magnitude can be achieved by this approach.
Benchmark calculations will be shown which demonstrate the accuracy and performance
of the approximations outlined above. Comparisons with experimental data will be
provided.
L7
Molecular Properties ’09 - Lectures
Three level optimization of the Hartree–Fock/Kohn–Sham energy
for reliable convergence to an optimized energy and for
generating localized molecular orbitals both for the occupied and
virtual orbital spaces
Branislav Jansı́k, Marcin Ziólkowski, Stinne Høst,
Mikael P. Johansson, Jeppe Olsen, and Poul Jørgensen
The Lundbeck Foundation Center for Theoretical Chemistry,
Department of Chemistry, University of Aarhus,
Langelandsgade 140, DK-8000 Århus C, Denmark
Trygve Helgaker
Centre for Theoretical and Computational Chemistry,
Department of Chemistry, University of Oslo,
P.O. Box 1033 Blindern, N-0315 Oslo, Norway
Abstract
A hierarchical optimization strategy will be introduced for minimizing the Hartree–Fock/Kohn–
Sham energy. It contains three levels (3L) 1) an atom in a molecule optimization 2) a valence basis
molecular optimization and 3) a full basis molecular optimization. The density matrix formed at
one level is used as starting density matrix at the next level with no loss of information. To ensure
fast and reliable convergence to a minimum the augmented Roothan–Hall (ARH) algorithm is used
in both the valence and full basis molecular optimizations. It is demonstrated that whereas the
standard Roothan–Hall approach with a DIIS convergence acceleration scheme may often fail to
converge to a minimum, the three level augmented Roothan–Hall (3L-ARH) scheme ensures fast
and reliable convergence to a minimum. The three level procedure further allows us to generate a
set of localized molecular orbitals both for the occupied and virtual orbital spaces.
L8
Molecular Properties ’09 - Lectures
From Computational Photobiology to the Design of an Ultrafast Biomimetic
Molecular Switch
Massimo Olivucci
Universitá di Siena, Siena, Italy & Bowling Green State University, OH, USA
E-mail: [email protected] and [email protected]
The developments in the field of
hybrid
quantum
mechanical/molecular
mechanical computational protocols based on
multiconfigurational quantum chemistry tools
have allowed the study of the excited-state
properties
of
chemically
different
chromophores embedded in different protein
environments. In particular a methodology
originally developed in our laboratory has
been applied to the investigation of the excited-state structure and properties of the
protonated Schiff-base retinal chromophore of bovine Rhodopsin and microbial Sensory
Rhodopsin photoreceptors. For Rhodopsin we have shown that it has been possible to
build a computer model of the receptor that reproduces the observed spectral behavior
and ultrashort excited state lifetime (see Figure above) [1]. More recently, these studies
have triggered the search for small synthetic organic molecules that may behave, in
solution, as the retinal chromophore in Rhodopsin. In particular, we looked for
photochromic molecules with close spectral features and capable to undergo a subpicosecond cis-trans isomerization with high efficiency upon light irradiation [2]. The
status of these ongoing studies will be discussed focusing on the systems that have
already been synthesized in our laboratories.
[1] L. M. Frutos, T. Andruniów, F. Santoro, N. Ferré and M. Olivucci Tracking the Excited State Time
Evolution of the Visual Pigment with Multiconfigurational Quantum Chemistry Proc. Nat. Acad. Sci.
2007, 104, 7764.
[2] A. Sinicropi, E. Martin, M. Ryasantsev, J. Helbing, J. Briand, D. Sharma, J. Léonard, S. Haacke, A.
Cannizzo, M. Chergui, V. Zanirato, S. Fusi, F. Santoro, R. Basosi, N. Ferré and M. Olivucci An Artificial
Molecular Switch that Mimics the Visual Pigment and Completes its Photocycle in Picoseconds Proc. Nat.
Acad. Sci., 2008, 105, 17642.
L9
Molecular Properties ’09 - Lectures
Divide-and-conquer linear-scaling calculation for polarizability
H.Nakai,1,2 M. Kobayashi,1,3 T. Touma,1 T. Akama,1 M. Fujii,1 and Y. Imamura1
1
Department of Chemistry and Biochemistry, School of Advanced Science and Engineering,
Waseda University, Tokyo 169-8555, Japan
2
Research Institute for Science & Engineering (RISE),
Waseda University, Tokyo 169-8555, Japan
3
Department of Theoretical and Computational Molecular Science,
Institute for Molecular Science (IMS), Okazaki 444-8585, Japan
Reciprocal dispersion
The divide-and-conquer (DC) method, which was proposed by Yang et al. [1,2], is one of the
linear-scaling techniques, avoiding explicit diagonalization of the Fock matrix and reducing the
Fock elements. The DC method was applied mainly to pure density functional theory (DFT) or
semi-empirical molecular orbital (MO) calculations. We have applied the DC method to the
Hartree-Fock (HF) and hybrid HF/DFT calculations and confirmed its reliability [3-5].
Furthermore, we have proposed an alternative linear-scaling scheme for obtaining the
second-order Møller-Plesset perturbation (MP2) and coupled-cluster with singles and doubles
(CCSD) energies based on the DC technique, namely, DC-MP2 [6,7] and DC-CCSD [8], which
evaluate the correlation energies of the total system by summing up DC subsystem contributions.
The energy density analysis (EDA) [9] scheme plays an important role to estimate the
non-redundant correlation energies of the individual subsystems. Recently, the DC codes for
DC-HF, DFT, MP2, and CC have been published through the GAMESS program package
(GAMESS Jan 09) [10].
78
This presentation gives a further development of the
Conventional
DC technique in order to calculate the polarizability. The
DC-TDCPHF method
76
combination of the DC technique and time-dependent
coupled-perturbed Hartree-Fock (TDCPHF) method was
74
investigated for the dynamical polarizability. Fig. 1
describes the refraction index at 589 nm (Na D-line) of
72
CnH2n+2 (n = 4-80), which are calculated by the
conventional and DC-based TDCPHF methods with the
70
6-31G** basis sets. Furthermore, the electron correlation
0
20
40
60
80
effect for evaluating the polarizability was investigated
Number of carbon n
by the finite-field (FF) method combining with the Fig. 1. Refraction index of CnH2n+2 (n =
4-80) calculated by the conventional
DC-MP2 and DC-CCSD methods.
and DC-based TDCPHF methods.
[1] W. Yang, Phys. Rev. Lett., 66, 1438 (1991).
[2] W. Yang and T.-S. Lee, J. Chem. Phys., 103, 5674 (1995).
[3] T. Akama, M. Kobayashi, and H. Nakai, J. Comput. Chem., 28, 2003 (2007).
[4] T. Akama, A. Fujii, M. Kobayashi, H. Nakai, Mol. Phys., 19-22, 2799 (2007).
[5] T. Akama, M. Kobayashi, and H. Nakai, Int. J.Quant. Chem., in press (2009).
[6] M. Kobayashi, Y. Imamura, and H. Nakai, J. Chem. Phys., 127, 074103 (2007).
[7] M. Kobayashi and H. Nakai, Int. J. Quant. Chem., 109 2227(2009)
[8] M. Kobayashi, and H. Nakai, J. Chem. Phys., J. Chem. Phys. 129, 044103 (2008).
[9] H. Nakai, Chem. Phys. Lett., 363, 73 (2002).
[10] M. Kobayashi, T. Akama, and H. Nakai, J. Comput. Chem. Jpn. 8, 1 (2009).
L10
Molecular Properties ’09 - Lectures
Calculation of local molecular properties using a subsystem density functional approach
Lucas Visscher
Section Theoretical Chemistry, Faculty of Scicnces, Amsterdam Center for Multiscale Modeling,
Vrije Universiteit Amsterdam, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands
Abstract
I will discuss calculation of molecular properties using the frozen density embedding method[1]
in which only the density of the central system of interest is optimized in a calculation of local
molecular properties. After a brief review of our earlier work[2,3,4] in this area I will present
new results on the treatment of NMR spin-spin couplings[5] and on the performance of GGA
kinetic energy functionals for coordination complexes[6].
[1] T. A. Wesolowski and A. Warshel, J. Phys. Chem. 97 (1993) 8050.
[2] C. R. Jacob and L. Visscher, J. Chem. Phys. 125 (2006) 194104.
[3] A. S. P. Gomes, Ch. R. Jacob, L. Visscher, PCCP 10 (2008) 5353.
[4] C. R. Jacob and L. Visscher, J. Chem. Phys. 128 (2008) 155102.
[5] A. Götz and L. Visscher, to be published
[6] S. M. Beyhan, A. Götz, C. R. Jacob and L. Visscher, to be published.
L11
Molecular Properties ’09 - Lectures
Linear-Scaling Calculation of Molecular Properties
for Large Molecules
Christian Ochsenfeld
Theoretische Chemie, Universität Tübingen
D-72076 Tübingen, Germany
www.uni-tuebingen.de/qc
The quantum-chemical calculation of molecular response properties for molecules
comprising 1000 and more atoms is an important challenge. The key for tackling such
system sizes is to reduce the increase of the computational effort with molecular size to
linear. Here, we first present density matrix-based schemes at Hartree-Fock (HF) and
density-functional theory (DFT) levels [1-4]. In combination with the Laplace approach
introduced earlier in different context by Almlöf and Häser [5], we are able to reduce
the matrix multiplication overhead for solving the CPSCF equations to a minimum [4].
Furthermore, we describe progress towards a linear-scaling MP2 method [6] that employs rigorous multipole-based integral estimates (MBIE) [7-9] for preselecting numerically significant contributions. MBIE allows to account for the 1/R coupling between
charge distributions, so that the distance decay for integral products of at least 1/R4 in
AO-MP2 theory can be exploited. The largest system computed at the MP2 level comprises 16 DNA base pairs with overall 1024 atoms and 10 674 basis functions (without
point-group symmetry and on one processor) [6]. As a first step towards properties other
than energetics, we have formulated AO-based MP2 energy gradients offering the potential to achieve linear scaling [10]. In this context, the Z-vector equations are introduced
fully in a density matrix-based fashion, which is closely related to our linear-scaling
CPSCF work [1-4].
[1]
[2]
[3]
[4]
[5]
[6]
C. Ochsenfeld, J. Kussmann, F. Koziol; Angew. Chem. Int. Ed. 43, 4485 (2004)
J. Kussmann, C. Ochsenfeld; J. Chem. Phys. 127, 054103 (2007)
J. Kussmann, C. Ochsenfeld; J. Chem. Phys. 127, 204103 (2007)
M. Beer, C. Ochsenfeld; J. Chem. Phys. 128, 221102 (2008)
M. Häser, J. Almlöf; J. Chem. Phys. 96, 489 (1992)
B. Doser, D. S. Lambrecht, J. Kussmann, C. Ochsenfeld;
J. Chem. Phys. 130, 064107 (2009)
[7] D. S. Lambrecht, C. Ochsenfeld; J. Chem. Phys. 123, 184101 (2005)
[8] D. S. Lambrecht, B. Doser, C. Ochsenfeld; J. Chem. Phys. 123, 184102 (2005)
[9] B. Doser, D. S. Lambrecht, C. Ochsenfeld; Phys. Chem. Chem. Phys. 10, 3335 (2008)
[10] S. Schweizer, B. Doser, C. Ochsenfeld; J. Chem. Phys. 128, 154101 (2008)
L12
Molecular Properties ’09 - Lectures
Cholesky Decomposition-based Ab initio Density Fitting:
Locality from Completeness
Francesco Aquilante, Laura Gagliardi, Thomas Bondo Pedersen, and Roland Lindh
Department of Physical Chemistry, Geneva University - Geneva, Switzerland
E-mail: [email protected]
A critical issue for any ab initio or density functional theory method which explicitly relies
on the two-electron integrals is represented by the fact that increasing the number of basis
functions per atom leads to a quartic scaling of the number of integral evaluations. The
Density Fitting (DF) approximation to the two-electron integral matrix1 tackles this socalled “basis set quality problem” by exploiting the near and exact linear dependences in
the product space of the atomic orbitals.
We have recently shown2 that Cholesky decomposition (CD) of the two-electron integral
matrix is a robust and general technique for generating auxiliary basis sets in DF approximations. Moreover, the accuracy of the approximation can be systematically improved by
lowering the decomposition threshold.
We will here demonstrate3 that the CD-based auxiliary basis sets introduce an inherent
locality in the fitting coefficients even when a long-ranged metric, such as the Coulomb
metric, is used. This property, which is not shared by existing standard auxiliary basis sets,
opens new opportunities for faster and reduced-scaling DF-based algorithms in quantum
chemistry.
References
1. J. L. Whitten, J. Chem. Phys. 58, 4496 (1973).
O. Vahtras, J. Almlöf and M. W. Feyereisen, Chem. Phys. Lett. 213, 514 (1993).
2. F. Aquilante, R. Lindh and T. B. Pedersen, J. Chem. Phys. 127, 114107 (2007).
3. F. Aquilante, L. Gagliardi, T. B. Pedersen and R. Lindh, J. Chem. Phys. 130, 154107
(2009).
1
L13
Molecular Properties ’09 - Lectures
Explicitly correlated molecular electronic wave functions:
Energies and analytic derivatives
Wim Klopper and Sebastian Höfener
Lehrstuhl für Theoretische Chemie,
Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
Christof Hättig
Lehrstuhl für Theoretische Chemie,
Ruhr-Universität Bochum, D-44780 Bochum, Germany
In wave function-based quantum chemistry, molecular electronic wave functions are
expanded in a basis of antisymmetrized products of one-particle functions, that is, orbitals. In practical calculations, this basis is incomplete, and basis-set truncation errors
occur. The basis can be increased in a systematic and optimal fashion, but nevertheless,
the basis-set truncation errors vanish only slowly as n−1 , where n is the number of orbitals
per atom. This slow convergence represents a major obstacle for accurate wave functionbased quantum chemistry, as computation times grow at least as n4 . The convergence
of computational results to the limit of a complete basis can be accelerated by utilizing
extrapolation procedures or by seeking alternatives to the expansion in a basis of antisymmetrized products of one-particle functions. In the present talk, the F12 method will be
discussed, which represents such an alternative. In the F12 methods, not only one-particle
functions are used, but also two-particle functions (Slater-type geminals), which depend
explicitly on the interparticle distances between the electrons in the molecule.
In previous work by Kordel et al., we have discussed the implementation—in the
Dalton program—of the analytic calculation of first-order molecular properties at the
explicitly correlated second-order Møller–Plesset level, including nuclear gradients. In the
present talk, we report our progress in the corresponding implementation in the Turbomole
program. Results will be presented for the analytic calculation of relaxed first-order
properties.
References
W. Klopper and J. Noga, in: Explicitly Correlated Functions in Chemistry and Physics – Theory
and Applications, J. Rychlewski (Ed.), Kluwer, Dordrecht, 2003, p. 149.
E. Kordel, C. Villani, and W. Klopper, J. Chem. Phys. 122, 214306 (2005).
W. Klopper, F. R. Manby, S. Ten-no, and E. F. Valeev, Int. Rev. Phys. Chem. 25, 427 (2006).
E. Kordel, C. Villani, and W. Klopper, Mol. Phys. 105, 2565 (2007).
L14
Molecular Properties ’09 - Lectures
Accurate calculation of molecular properties using explicitly
correlated coupled cluster methods
Hans-Joachim Werner
Institut für Theoretische Chemie, Universität Stuttgart,
Pfaffenwaldring 55, 70569 Stuttgart, Germany
We demonstrate the practical performance of the simple and efficient explicitly correlated CCSD(T)-F12x (x=a,b) methods we recently proposed[1,2]. Great enhancements in
basis set convergence are not only achieved for reaction energies, but also for a wide variety of molecular properties, including atomization energies, electron affinities, ionization
potentials, equilibrium geometries, vibrational spectroscopic constants, and intermolecular interaction energies[2-4].
In most cases the intrinsic accuracy of the CCSD(T) method is already reached with
aug-cc-pVTZ or VTZ-F12[5,6] basis sets; sometimes even aug-cc-pVDZ or VDZ-F12
sets are sufficient. Since the additional cost of the F12 correction is small compared
to that of the CCSD(T) calculation itself, the applicability of accurate coupled cluster
methods is greatly extended.
The steep scaling of the computational as a function of the molecular size can be
reduced by using localized orbitals and local approximations. We present a new local
CCSD-F12 method[7], in which the explicitly correlated terms not only improve the basis set convergence, but also eliminate the errors caused by the local approximations. This
is achieved by a modification of the strong orthogonality projector[8,9], which makes it
possible that the configurations which are neglected in the conventional local wavefunction are effectively included in the explicitly correlated part. It is demonstrated for a large
set of reaction energies that the CCSD-F12 and LCCSD-F12 methods yield the same
accuracy.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
T.B. Adler, G. Knizia and H.-J. Werner, J. Chem. Phys 127, 221106 (2007).
G. Knizia, T.B. Adler and H.-J. Werner, J. Chem. Phys, 130, 054104 (2009).
G. Rauhut, G. Knizia and H.-J. Werner, J. Chem. Phys, 130, 054105 (2009).
O. Marchetti and H.-J. Werner, Chem. Phys. Phys. Chem. 10, 3400 (2008).
K.A. Peterson, T.B. Adler and H.-J. Werner, J. Chem. Phys. 128, 084102 (2008).
K. E. Yousaf and K. A. Peterson, J. Chem. Phys. 129, 184108 (2008).
T. B. Adler and H.-J. Werner, submitted for publication.
H.-J. Werner, J. Chem. Phys. 129, 101103 (2008).
T. B. Adler, F. R. Manby and H.-J. Werner, J. Chem. Phys. 130, 054106 (2009).
L15
Molecular Properties ’09 - Lectures
A Determination of the Ionization Energies, Electron Affinities
and Singlet-Triplet Energy Gaps of Benzene and Linear
Acenes within Chemical Accuracy
by
Balázs Hajgatóa,b M.S. Deleuzeb, D. J. Tozerc, P. Geerlingsa F. De Profta
(a) Vrijre Universiteit Brussel, Eenheid Algemene Chemie, Pleinlaan 2, B-1050 Brussels, Belgium
(b) Universiteit Hasselt, Departement SBG, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
(c) Durham University, Department of Chemistry, South Road, DH1 3LE Durham, UK
A benchmark theoretical determination of the vertical ionization energy thresholds [1], electron
affinities [2] and singlet-triplet energy gaps [3] of benzene and linear oligoacenes ranging from
naphthalene to hexacene or heptacene is presented, using the principles of a Focal Point Analysis.
These energy differences have been obtained from a series of single-point calculations at the
Hartree-Fock (HF), second-, third-, and partial fourth order Møller–Plesset (MP2, MP3, MP4SDQ)
levels, and from coupled cluster calculations including single and double excitations (CCSD) as
well as perturbative estimates of connected triple excitations [CCSD(T)], using basis sets of
improving quality. The convergence properties of these energy differences as a function of the size
of the basis set and order attained in electronic correlation are exploited through extrapolations of
CCSD(T) results to asymptotically complete basis sets (cc-pV∞Z, aug-cc-pV∞Z), which enables
for all targets theoretical insights within chemical accuracy (0.04 eV). Adiabatic ionization energies,
electron affinities and singlet-triplet energy gaps have been further calculated by incorporating
corrections for zero-point vibrational energies and for geometrical relaxations. Highly quantitative
insights into experiments employing electron transmission spectroscopy on systems characterised
by negative electron affinities, corresponding to so-called metastable anions, are in particular
amenable with such an approach, provided diffuse atomic functions are deliberately removed from
the basis set, in order to enforce confinement in the molecular region and enable a determination of
pseudo-adiabatic electron affinities (with respect to the timescale of nuclear motions). Comparison
was made with calculations of electron affinities employing Density Functional Theory and
especially designed models that exploit the integer discontinuity in the potential or incorporate a
potential wall in the unrestricted Kohn-Sham orbital equation for the anion. The present study also
confirms the adequacy of the Outer Valence Green’s Function approach for the ionization energies
and electron affinities of large conjugated π-systems, but demonstrates an exacerbation of the
dependence of correlated energy differences onto the basis set with increasing system size.
References
[1] M. S. Deleuze, L. Claes, E. S. Kryachko and J. -P. François, J. Chem. Phys., 119, 3106 (2003)
[2] B. Hajgató, M. S. Deleuze, D. J. Tozer, F. De Proft, J. Chem. Phys., 129, 084308 (2008).
[3] B. Hajgató, M. S. Deleuze, D. Szieberth, F. De Proft, and P. Geerlings (in preparation).
L16
Molecular Properties ’09 - Lectures
Canonical Transformation Theory for Large-scale
Multireference Electronic Structure Calculations
Takeshi Yanai and Yuki Kurashige (Institute for Molecular Science, Japan)
Garnet K.-L. Chan, Debashree Ghosh, Eric Neuscamman (Cornell University, U.S.A.)
Canonical transformation (CT) for many-body theory [1-4] has been implemented to
solve large-scale multireference quantum chemistry problems accurately. The theory
constructs a renormalization structure of the high-level dynamic electron correlation in an
effective Hamiltonian where the bare Hamiltonian is transformed by the unitary exponential
correlation operator, which in parallel acts on the reference multi-configurational
wavefunction that describes the substantial static correlation. A compact form of the
high-level dynamic correlations is handled in CT for the efficient computation by
exploiting robust truncations of higher-order perturbatives in three-particle operators and
density matrices. We demonstrate large-scale multireference CT calculations performed
with the computationally efficient implementation. The method has recently been able to be
interfaced to the DMRG-CASSCF (Density Matrix Renormalization Group-Complete
Active Space Self-Consistent Field) implementation [5-6] of Chan’s group development,
and resultantly the large-size multireference, which are statically correlated descriptions
from the DMRG-CASSCF calculations with the unprecedentedly large CAS, have been
handled in the subsequent CT calculations.
We present another implementation of the high-performance DMRG in which we have
made some improvements that enhance applicability of DMRG to electronic structure study
on transition metal complexes such as Cr2 or Cu2O2 core [7].
1.
2.
3.
4.
5.
6.
7.
T. Yanai and G. K-L. Chan, “Canonical transformation theory for multireference
problems”, J. Chem. Phys. 124, 194106 (2006) (16 pages).
G. K-L. Chan and T. Yanai, “Canonical Transformation Theory for Dynamic Correlations
in Multi-reference Problems”, Advances in Chemical Physics Vol. 134, pp. 343-384
(2007).
T. Yanai and G. K-L. Chan, “A Canonical Transformation Theory from Extended Normal
Ordering”, J. Chem. Phys. 127, 104107 (2007) (14 pages).
E. Neuscamman, T. Yanai, G. K-L. Chan, “Quadratic canonical transformation theory and
higher order density matrices,” J. Chem. Phys., 130, 124102 (2009).
D. Ghosh, J. Hachmann, T. Yanai and G. K-L. Chan, “Orbital Optimization in Density
Matrix !"#$%&'()*'+)$#, -%$./0, 1)+2, '//()3'+)$#4, +$, /$(5"#"4, '#6, 7-carotene”, J. Chem.
Phys. 128, 144117 (2008) (14 pages).
T. Yanai, Y. Kurashige, D. Ghosh, and G. K-L. Chan, “Accelerating convergence in
iterative solution for large-scale complete active space self-consistent-field calculations”,
Int. J. Quantum Chem. (Hirao Issue) 109, 2178-2190 (2009).
Y. Kurashige and T. Yanai, J. Chem. Phys. submitted.
L17
Molecular Properties ’09 - Lectures
Molecular Properties for Second-Order
Generalized Van Vleck Perturbation Theory
Daniel P. Theisa, Yury G. Khaita,b, Mark R. Hoffmanna, and Sourav Palc
a
Department of Chemistry, University of North Dakota, Grand Forks, ND 58202-9024,
USA, bRussian Scientific Center “Applied Chemistry”, 14 Dobrolyubova Ave, St.
Petersburg, 197198 Russia, National Chemical Laboratory, Pune, 411 008 India
Keywords: GVVPT2, multireference perturbation theory, response properties, multipole
moments
The constrained variational approach (CVA)1 has been applied to the recently developed
second-order Generalized Van Vleck Perturbation Theory (GVVPT2)2 variant of
multireference perturbation theory (MRPT) to produce lucid formulas for the responses
of the electronic energy to external perturbation. Computational implementation of the
formulas lead straightforwardly to efficient algorithms. In particular, it is shown that the
CVA allows facile treatment of the highly nonlinear level shift, which permits GVVPT2
to circumvent in the so-called intruder state problem, even for potential energy surfaces
in close proximity. Calculation of molecular properties is shown to be computationally
feasible for any system for which resources for calculation of the energy are available. In
the present work, one-electron molecular properties (specifically, electric multipole
moments up to hexadecapoles) and first derivatives with respect to nuclear perturbations
are presented.
1
K. R. Shamasundar and S. Pal, Int. J. Mol. Sci. 3, 710 (2002); K. R. Shamasundar, S.
Asokan and S. Pal, J. Chem. Phys. 120, 6381 (2004).
2
Y. G. Khait, J. Song and M. R. Hoffmann, J. Chem. Phys. 117, 4133 (2002).
L18
Molecular Properties ’09 - Lectures
On a Manifestly Covariant Many-Body Theory
Or
Tinkering with the Laws of Physics
M. Nooijen, D. Upadhyay, L. Huntington and M. Akash
Department of Chemistry
University of Waterloo
Ontario, Canada
The so-called no-pair Dirac-Coulomb-(Breit) equation is presently the basis for
our most accurate, yet quite generally applicable, description of many-body relativistic
quantum chemistry. However, from a fundamental point of view this procedure has
severe issues: it is not Lorentz-invariant and moreover the no-pair projection on positive
energy states is not uniquely defined.
In this presentation possibilities for a manifestly covariant mechanics will be
explored, both at a classical and a quantum mechanical level. The most striking feature of
the formulation is that every individual particle is described by 4 spacetime coordinates,
while the evolution of the system as a whole is associated with a single ‘Newtonian’ time
parameter. The notion of simultaneity is reintroduced in relativistic mechanics and this
allows the definition of conserved total energy, total linear and total angular momentum.
Interestingly, conventional Newtonian and relativistic mechanics can both be formulated
in a Lorentz invariant fashion, demonstrating that a finite maximum velocity and Lorentz
invariance are distinct features. The corresponding quantum theories are obtained through
identification of Poisson brackets and operator commutation relations, and are a fairly
straightforward generalization from 3 to 4 dimensions. We will consider both scalar and
spinor representations of the quantum theory and present solutions for the Hydrogen
atom, but using the SO(4) rather than the Lorentz SO(3,1) metric.
The attractive features of our approach are mathematical consistency and a
satisfaction of desirable symmetries, while agreement with experiment is at this stage
considered to be of secondary importance. In addition, we found intriguing possibilities
to create exactly solvable models for many-particle systems using a massless, spinorial
representation. While these models may not be physically correct, they may nonetheless
be interesting from a mathematical and computational perspective, as they describe
many-body wave equations for arbitrary many interacting particles, which can be solved
analytically. Current efforts are still in an exploratory stage of development.
L19
Molecular Properties ’09 - Lectures
Connection between molecular properties and
intermolecular interaction potentials
Krzysztof Szalewicz
Department of Physics and Astronomy, University of Delaware, Newark, DE 19716
Intermolecular forces determine properties of condensed phases and of biological systems. These
properties can be predicted provided the intermolecular interaction potential energy surfaces (force
fields) are known. Currently, the majority of force fields used in simulations of condensed phases
and of biomolecular systems are empirical in nature, i.e., were obtained by fitting experimental
data. However, with recent progress in electronic structure methods, potentials computed from
first principles are surpassing the empirical ones in terms of quality of predictions, as shown, e.g.,
for water [1], benzene [2], and cyclotrimethylene trinitramine [3]. In particular, it is now possible to
obtain pair potentials for fairly large systems, including monomers containing about 30 atoms, due
to the development of symmetry-adapted perturbation theory (SAPT) based on density-functional
theory (DFT) description of monomers [SAPT(DFT)] [4–7]. This method gives results comparable
in accuracy to those of the coupled-cluster approach with single, double, and noniterative triple
excitations at a much lower computational cost.
At large intermonomer separations, intermolecular potentials are well represented by asymptotic expansions in inverse powers of intermonomer separation, Cn /Rn . The leading coefficients
Cn , arising in the first, second, and partly third order of perturbation theory, can be computed
using exclusively properties of monomers such as multipole moments, polarizabilities, and hyperpolarizabilities [8]. The asymptotic dispersion energy in the third order can be expressed by the
dynamic hyperpolarizabilities only for atoms, whereas for molecules one has to use also some quantities similar to hyperpolarizabilities which, however, are not physical observables [9]. Clearly, it
is very desirable to include the asymptotic expansions as a component of force fields. This is
particularly appropriate for force fields fitted to SAPT interaction energies since these energies
seamlessly connect to asymptotic interaction energies at each order of perturbation [10–12]. For
construction of system-specific potentials, the use of the correct asymptotics fully computed from
monomer molecular properties is a solved problem and should become the standard in the field.
In the case of transferable fields, there are several open issues. Currently, some empirical force
fields utilize one component of the asymptotic expansion, the electrostatic energy, with multipoles
represented by partial atomic charges fitted to ab initio computed charge densities. Virtually all
6 , where r is atom-atom distance. However, the coefficients
such fields contain also terms C6,ab /rab
ab
C6,ab are just free parameters in the fitting procedures and, consequently, these terms rather poorly
recover asymptotic dispersion energies, with errors of the order of 30% [13]. An unresolved question
how to reliably determine the partial charges and the Cn,ab constants independent of the specific
molecules that contain given atoms will be discussed.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
R. Bukowski, K. Szalewicz, G. C. Groenenboom, and A. van der Avoird, Science 315, 1249 (2007).
R. Podeszwa, R. Bukowski, and K. Szalewicz, J. Chem. Theo. Comp. 2, 400 (2006).
R. Podeszwa, B. M. Rice, and K. Szalewicz, Phys. Rev. Lett. 101, 115503 (2008).
A. J. Misquitta, B. Jeziorski, and K. Szalewicz, Phys. Rev. Lett. 91, 033201 (2003).
A. Hesselmann, G. Jansen, and M. Schütz, J. Chem. Phys. 122, 014103 (2005).
R. Podeszwa, R. Bukowski, and K. Szalewicz, J. Phys. Chem. A 110, 10345 (2006).
A. J. Misquitta, R. Podeszwa, B. Jeziorski, and K. Szalewicz, J. Chem. Phys. 123, 214103 (2005).
B. Jeziorski, R. Moszyński, and K. Szalewicz, Chem. Rev. 94, 1887 (1994).
K. Pernal and K. Szalewicz, J. Chem. Phys. 130, 034103 (2009).
E. M. Mas, K. Szalewicz, R. Bukowski, and B. Jeziorski, J. Chem. Phys. 107, 4207 (1997).
R. Bukowski, J. Sadlej, B. Jeziorski, P. Jankowski, K. Szalewicz, S. A. Kucharski, H. L. Williams, and
B. S. Rice, J. Chem. Phys. 110, 3785 (1999).
[12] E. M. Mas, R. Bukowski, K. Szalewicz, G. C. Groenenboom, P. E. S. Wormer, and A. van der Avoird,
J. Chem. Phys. 113, 6687 (2000).
[13] K. Patkowski et al., to be published.
L20
Molecular Properties ’09 - Lectures
Coupled cluster treatment of intramonomer correlation effects in
symmetry-adapted perturbation theory
Tatiana Korona
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
Accurate calculations of the interaction energy within the formalism of symmetryadapted perturbation theory (SAPT) would be impossible without an inclusion of electron
correlation effects inside the interacting molecules. So far the intramonomer correlation
has been described either by Møller-Plesset theory, giving the SAPT(MP) method, or by
density-functional theory, resulting in the SAPT(DFT) approach. In this presentation an
alternative treatment of the intramonomer correlation effects is proposed, which is based
on the coupled cluster description of monomers. An introduction of the new SAPT(CC)
method has been greatly facilitated by expressing all components of the SAPT interaction
energy in terms of monomer properties, such as one-electron reduced density matrices,
cumulants of two-electron reduced density matrices, frequency-dependent density susceptibilities and density-matrix susceptibilities. These properties have been then retrieved
from expectation-value coupled cluster theory and its generalization to second-order dynamic molecular properties. The resulting SAPT(CC) approach is not affected by the
known convergence problems of the Møller-Plesset series or by a dependence of the results on the quality of a DFT functional. A practical implementation of SAPT(CC) has
been limited to the case of monomers described by coupled cluster theory restricted to
single and double excitations (CCSD). A density-fitting has been applied to CCSD density susceptibilities and density-matrix susceptibilities in order to reduce the computational cost of obtaining the dispersion and exchange-dispersion energies. A performance of
SAPT(CCSD) will be examined for representative non-covalent complexes by a comparison with the SAPT(MP) and SAPT(DFT) methods, as well as with interaction energies
calculated by supermolecular CCSD(T), CCSDT(Q), and CCSDTQ theories. Individual
energy components of all SAPT approaches will be also presented and discussed.
L21
Molecular Properties ’09 - Lectures
Atomic charge densities and polarizabilities.
Richard J. Wheatley and Timothy C. Lillestolen
School of Chemistry
University of Nottingham
University Park
Nottingham NG5 4FB
UK
Dividing molecular properties into atomic or functional group contributions is
essential to bridge the gap between chemical computations and chemical concepts.
Recently, we introduced Iterated Stockholder Atoms (T. C. Lillestolen and R. J.
Wheatley, Chem. Commun., 2008, 5909; J. Chem. Phys., 2009, in press) and showed
that they are unique, easy to calculate using standard DFT integration grids, and that
they give atomic shapes and charges in accord with expectations.
In this work, we consider the practical value of ISAs in quantitative work. Three
questions are addressed. Firstly, how quickly does the spherical harmonic expansion
of an ISA converge? A sensitive test of this is the Coulombic interaction between two
molecules, and examples including the water dimer are shown. Secondly, can the
radial dependence of each important spherical harmonic component of the ISA
density be represented by a convenient mathematical function? Finally, how similar
are ISAs for ‘chemically similar’ atoms in different molecules?
We then turn to the problem of representing molecular polarizabilities in terms of
atomic contributions. Atomic polarizabilities are important properties in their own
right, and they can also be used to calculate atomic dispersion energy coefficients,
which can be used in constructing ab initio force fields. We discuss our localisation
scheme for calculating atomic polarizabilities and dispersion energy coefficients from
the molecular response properties (TCL and RJW, J. Phys. Chem. A, 2007, 111,
11141; RJW and TCL, Molec. Phys., 2008, 106, 1545), which has been used to
produce atomic dipole, quadrupole and octopole polarizabilities and dispersion energy
coefficients. The results are compared with other literature values for atomic
polarizabilities, and we investigate the possibility of extending the calculations to
higher accuracy and to larger molecules.
L22
Molecular Properties ’09 - Lectures
Is the adiabatic approximation sufficient to account for the
post-Born-Oppenheimer effects on molecular electric dipole moments?
Sandra L. Hobson and Edward F. Valeev∗
Department of Chemistry, Virginia Tech, Blacksburg, VA 24061, USA
Attila G. Császár
Laboratory of Molecular Spectroscopy, Institute of Chemistry,
Eötvös University, H-1518 Budapest 112, P.O. Box 32, Hungary
John F. Stanton
Department of Chemistry and Biochemistry,
The University of Texas at Austin, Austin, TX 78712, USA
We estimated the post-Born-Oppenheimer (post-BO) contribution to electric dipole
moments by finite-field derivatives of the diagonal Born-Oppenheimer correction computed with correlated electronic wave functions. The new method is used to examine
the effect of isotopic substitution on the dipole moments of the HD, LiH, LiD, and H2 16 O
molecules. The nonzero dipole moment of HD is solely due to the post-BO effect and is
predicted within a few percent of the best experimental and theoretical results. The postBO contribution to the dipole moment in LiH and LiD is comparable in magnitude to that
in HD, but the difference in total adiabatic dipole moments of LiH and LiD is dominated
by the vibrationally averaged BO contribution, and the post-BO contribution is relatively
unimportant. However, the post-BO contribution to the dipole moment in H2 O is much
larger than the vibrationally averaged BO contribution determined by Lodi et al. (J. Chem.
Phys. 128, 044304 (2008)) and is twice as large as the discrepancy between their best theoretical BO estimate and the most recent experimental result. Our findings suggest that (1)
the post-BO effects on the electric dipole moments can be important for modeling highresolution molecular spectra and (2) the adiabatic approximation is sufficient to estimate
such effects in well-behaved species to a few percent accuracy.
∗ Electronic
address: [email protected]
L23
Molecular Properties ’09 - Lectures
Perturbative theory of nonadiabatic effects in molecules
Krzysztof Pachucki
Institute of Theoretical Physics, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland
Jacek Komasa
Quantum Chemistry Group, Department of Chemistry,
A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
Molecular calculations aiming at spectroscopic accuracy must, apart from adiabatic and relativistic corrections, take into account the nonadiabatic effects. In this
talk, a rigorous perturbative approach to the finite nuclear mass effects on molecular
energy and wave function will be presented. With the adiabatic wave function as a
reference state and the electron-to-nucleus mass ratio as the expansion parameter,
a systematic perturbative scheme is developed. For the simplest case of a diatomic
molecule, the leading nonadiabatic effects on rovibrational levels can be described in
terms of three radial functions: the nonadiabatic potential, the R-dependent nuclear
mass, and the R-dependent moment of inertia. The radial nuclear equation constructed out of these functions can be solved simultaneously for all the rovibrational
states. We demonstrate that the new methodology within the leading (me /mp )2 order, when applied to H2 and D2 molecules, yields the energy levels with an accuracy
of ∼ 0.001 cm−1 [1, 2]. Applications to phenomena in which the nonadiabatic effects
are essential like the electric dipole rovibrational transitions in the HD molecule [3]
or ortho-para transition in H2 [4] will be discussed.
[1] K. Pachucki and J. Komasa, J. Chem. Phys. 129, 034102 (2008).
[2] K.Pachucki and J.Komasa, J. Chem. Phys. 130, 164113 (2009).
[3] K. Pachucki and J. Komasa, Phys. Rev. A 78, 052503 (2008).
[4] K. Pachucki and J. Komasa, Phys. Rev. A 77, 030501(R) (2008).
L24
Molecular Properties ’09 - Lectures
Excited states from TDDFT: Predicting Failures & Improving Accuracy
David J Tozer
Department of Chemistry
Durham University
South Road, Durham,
DH1 3LE UK
[email protected]
www.dur.ac.uk/d.j.tozer
For GGA and hybrid exchange-correlation functionals, we have demonstrated [1] a
broad correlation between the error in a time-dependent density functional theory
(TDDFT) excitation energy and the degree of spatial overlap between the occupied
and virtual orbitals involved in the excitation. We used this to propose a diagnostic
test for identifying problematic charge-transfer (CT) excitations: when the overlap
drops below a prescribed threshold then the excitations become unreliable. We have
also demonstrated that this correlation is essentially eliminated using Coulombattenuated functionals, yielding significantly improved CT excitations.
In this talk, I shall review our most recent work in this area, including the use of basis
function scaling [2] and application to triazene chromophores [3].
[1] MJG Peach, P Benfield, T Helgaker, DJ Tozer. J. Chem. Phys. 128 044118 (2008)
[2] MJG Peach, DJ Tozer. J. Mol. Struct. (THEOCHEM) DOI:10.1026/j.theochem.2009.09.009 (2009)
[3] MJG Peach, CR Le Sueur, K Ruud, M Guillaume, DJ Tozer. PCCP 11 4465 (2009)
L25
Molecular Properties ’09 - Lectures
Exploring Electron Transfer and Bond Breaking with Constrained DFT
Troy Van Voorhis
Department of Chemistry
Massachusetts Institute of Technology
77 Massachusetts Ave.
Cambridge, MA 02139
This talk will highlight ongoing work being carried out in our group aimed at developing
methods that can accurately simulate the reaction dynamics involving electron transfer
and bond breaking/forming. Specifically, this talk will focus on the electronic structure
problem inherent in describing electron transfer: How can we treat charge transfer states
on the same footing with the electronic ground state? How do we make connections
between a phenomenological picture like Marcus theory and a more rigorous approach
like density functional theory (DFT)? How do we describe bond formation (in particular
proton transfer) that is often intimately connected with the process of electron transfer?
Many of our results will hinge on the use of constrained DFT to model physically
motivated constructs, such as diabatic reactant and product states. Time permitting, we
will mention some applications of these methods to organic light emission, photoinduced
dynamics and/or redox catalysis.
L26
Molecular Properties ’09 - Lectures
Time Dependent Density Functional Theory Calculations of Near-Edge
X-ray Absorption Fine Structure
Nicholas A. Besley∗
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Advances in modern synchrotron sources have provided spectroscopic techniques in the x-ray
region with much greater sensitivity and resolution. This has increased the scope of these methods
to be used as analytical tools, and provided x-ray spectroscopy with a richness in structure that
can match more traditional UV spectroscopy combined with the advantage that x-ray spectroscopy
provides a local probe of structure. Currently, near edge x-ray absorption fine structure (NEXAFS)
is used in a wide variety of fields, including materials science and biological chemistry. In the future,
it is likely that the application of these techniques will increase, fueling the demand for accurate
calculations of core excited states.
Time-dependent density functional theory (TDDFT) can
provide an efficient approach to computing NEXAFS spectra.
butadiene
The main problem with TDDFT calculations of core excited
states is that core excitation energies computed with standard
exchange-correlation functionals are too low compared with
experiment, and the extent of this underestimation increases
with the nuclear charge of the atomic centers on which the
core orbitals are localised.
284
288
290
286
Energy (eV)
292
1838 18
Experimental and computed
ethane
X-ray absorption spectra
This failure of TDDFT is associated with the self-interaction error. In this talk, it will be shown
that the self-interaction error at short-range interelectronic distances is important. A new short286 288 290 292 294 296 298
range corrected hybrid exchange-correlation functional with increased Hartree-Fock
exchange in the
Energy (eV)
short-range is introduced, and demonstrated to improve the calculated core-excitation energies to a
level of accuracy which is comparable to excitations in the ultra-violet region.
L27
2465
Molecular Properties ’09 - Lectures
Treatment of correlation in Density Matrix Functional Theory
Daniel R. Rohr,1,2,∗ K. Pernal,1,2 O. V. Gritsenko,1 and E. J. Baerends1
1
Afdeeling Theoretische Chemie, Vrije Universiteit, Amsterdam, The Netherlands
2
Institute of Physics, Technical University of Łódź, Łódź, Poland
∗
corresponding author: [email protected]
While Density Functional Theory (DFT) is successfully applied to many problems in Quantum
Chemistry it fails to describe bond breaking processes correctly. The reason is a lack of static correlation. We present a Density Matrix Functional (DMF) that captures dynamical and static correlation.
This is demonstrated for the dissociation curve of the ten-electron hydrides [1].
In Density Matrix Functional Theory (DMFT) all orbitals are fractionally occupied. The contribution of a pair of orbitals to the exchange correlation energy is regulated by a function of the occupation
numbers. We show that two natural choices suffice to obtain excellent results [2]. The well-known
exchange-type contribution and a square root dependence is used. The latter is taken from the exact
functional in the two-electron case [3].
For the correct description of the dissociation curve it is necessary to identify the bonding and anti
bonding orbitals. This is done with a switching function. It smoothly switches between the weakly
correlated case at equilibrium and the strongly correlated case at the dissociation limit.
Our functional (AC3) performs excellently on the dissociation curves of the ten-electron hydrides.
The average absolute error at equilibrium distance is 3.3%. The maximum error along the dissociation
curve is ca. 9 kcal/mol. The maximum is typically found at intermediate bond distances.
AC3 outperforms all competing functionals, HF, BLYP and other DMF like ML [4] and PNOF0 [5]
in the dissociation region. All competitors yield a qualitatively wrong dissociation curve, severely
underestimating the stability at the dissociation limit. In contrast, AC3 dissociates to the correct limit.
H2O dissociation curve
AC3
ML /
PNOF0
Energy
HF
MRCI
BLYP
Distance
Keywords: DMFT, strong correlation, dissociation curve
[1] D. R Rohr, K. Pernal, O. V. Gritsenko, and E. J. Baerends, J. Chem. Phys. 129, 164105 (2008).
[2] O. V. Gritsenko, K. Pernal, and E. J. Baerends, J. Chem. Phys. 122, 204102 (2005).
[3] P. O. Löwdin, and H. Shull, Phys. Rev. 101, 1730 (1956).
[4] M. A. L. Marques, and N. N. Lathiotakis, Phys. Rev. A 77, 032509 (2008).
[5] P. Leiva, and M. Piris, J. Chem. Phys. 123, 214102 (2005).
L28
Molecular Properties ’09 - Lectures
Relativistic, QED, and finite nuclear mass effects in the theory of
magnetic properties
Krzysztof Pachucki
Institute of Theoretical Physics, University of Warsaw,
Hoża 69, 00-681 Warsaw, Poland
Abstract
The perturbative theory of the magnetic interaction in light atoms and molecules is presented.
The finite nuclear mass, relativistic, and quantum electrodynamics (QED) effects are considered.
We demonstrate the significance of widely neglected nuclear mass (recoil) corrections to the magnetic interactions, such as the shielding constant. Considering relativistic and QED corrections,
the only consistent approach for light atoms or molecules, has to be based on the expansion in
the fine structure constant α, but not on the multi-electron Dirac equation. We present highly
accurate calculations including 1-loop QED corrections for the shielding constant in 3 He. Obtained
results are not in good agreement with former calculations based on the Dirac-Coulomb equation.
Finally, we present very precise calculation of the electron g-factor in hydrogen-like carbon including 1- and 2-loop QED effects, which by comparison with experimental result, make possible the
accurate determination of the electron mass.
L29
Molecular Properties ’09 - Lectures
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L30
Molecular Properties ’09 - Lectures
Ab initio calculations of magnetic interaction parameters in
molecules-based materials
S. Nishihara a), R. Takeda, a) M. Shoji, a) S. Yamanaka b), Y. Kitagawa a),
T. Kawakami a),M. Okumura a) and K. Yamaguchia,c)
a) Department of Chemistry, Graduate School of Science, Osaka University
b) Laboratory of Protein Informatics, Research Center of Structural and Functional
Proteomics, Institute for Protein Research, Osaka University
c) Toyota Physical & Chemical Research Institute, Nagakute, Aichi
First principle calculations of magnetic interaction parameters have been performed
to elucidate magnetic properties of molecules-based materials such as organic
ferromagnets, single molecule magnet, chiral molecular magnet, so on. To this end,
isotropic exchange (J), zero-field splitting (D, E) and Dzyaloshinskii-Moriya (DM) (d)
parameters have been calculated using our own GSO-X program, where brokensymmetry (BS) Hartree-Fock (HF), Kohn-Sham (KS) DFT and hybrid DFT, resonating
BS (RBS) and BS configuration interaction (CI) methods by the use of general spin
orbitals (GSO), two component spinors, including spin-orbit (SO) interaction are
feasible [1,2]. As an example, we first performed the resonating CI (Res CI) using two
UHF coupled-cluster (CC) configurations with up-down (R) and down-up (L) spin
configurations, namely diradical configurations, to calculate J values
Res CI = CR R + CL L .
(1)
As an approximation to Res UCC, approximate spin projection (AP) procedure for UCC
(APUCC) was also performed for relatively larger diradicals. These computations
were performed with combining the ACES II code [4] with an original Res-CI code
developed by Nishihara [5]. Resonating UHF and GHF(GSO) CI calculations were
performed for triangular systems with so-called spin flustration effects. GSO CI
including SO effect was performed to determine DM parameter, which is crucial for
discussion of chiral magnetism. Hybrid DFT methods such as UB2LYP were
optimized to reproduce J values with APUCC for applications to biomolecular systems
involving bi- and multi-nuclear transition metal complexes such as Mn4O4 and 8Fe-7S
clusters.
[1] K. Yamaguchi, Chem. Phys. Lett. 33, 330. 35, 230 (1975).
[2] K. Yamaguchi, Appl. Quant. Chem. (V. H. Smith et al Eds., Reidel, 1986) p155.
[3] R. Takeda, S, Yamanaka, M. Shoji and K. Yamaguchi, Int. J. Quant. Chem. 107,
1328 (2007).
[4] J. Stanton et al. Int. J. Quant. Chem. Symp. 26, 879 (1992). Mainz-Austin-Budapest
version of ACES II: http://www.aces2.de./
[5] S. Nishihara et al. 2008, Int J Quant Chem. 108,2966; J. Phys. Cond. Mat., 21,
064227 (2009)
L31
Molecular Properties ’09 - Lectures
Local hybrid functionals: Implementation and validation of
coupled-perturbed Kohn-Sham calculations of EPR parameters
Alexei V. Arbuznikov, Martin Kaupp
Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
The accuracy of molecular properties calculated within Kohn-Sham density
functional theory is mainly determined by the exchange-correlation functional employed.
Local hybrid functionals (local hybrids) that incorporate exact-exchange (EXX) energy
density in a position-dependent fashion [1] provide a promising new generation of
orbital-dependent functionals for the simultaneous accurate description of atomization
energies, reaction barriers, etc. First successful local hybrids have been constructed and
validated for various properties in our works [2-5].
One of the generally accepted ways to implement orbital-dependent functionals
self-consistently consists in constructing their functional derivatives with respect to the
orbitals (FDOs). The presence of the position-dependent EXX admixture in local
hybrids leads to the appearance of more sophisticated general non-local operators in the
corresponding FDOs comparing to traditional global hybrids (like, e.g., B3LYP).
Evaluation of linear-response magnetic properties requires iterative solution of the
coupled-perturbed Kohn-Sham (CPKS) equations. While such CPKS implementations
are well-known for global hybrids [6,7], this does not hold for local hybrids.
Here we derive and implement the CPKS scheme for local hybrids (and other
functionals of the hyper-GGA type) and use the approach in calculations of EPR gtensors for main-group and transition-metal compounds. Thermo-chemically successful
local hybrids yield also good results for g-tensors. The CPKS scheme can be used for
evaluation of other second-order response properties like NMR chemical shifts,
magnetic susceptibilities, etc.
References:
[1] Jaramillo, J; Scuseria, G. E.; Ernzerhof, M. J. Chem. Phys. 2003, 118, 1068.
[2] Bahmann, H.; Rodenberg, A.; Arbuznikov, A. V.; Kaupp, M. J. Chem. Phys. 2007,
126, 011103.
[3] Kaupp, M.; Bahmann, H.; Arbuznikov, A. V. J. Chem. Phys., 2007, 127, 194102.
[4] Arbuznikov, A. V.; Kaupp, M. Chem. Phys. Lett. 2007, 440, 160.
[5] Arbuznikov, A. V.; Kaupp, M. Chem. Phys. Lett. 2007, 442, 496.
[6] Kutzelnigg, W. Israel J. Chem. 1980, 19, 193.
[7] Kaupp, M.; Reviakine, R.; Malkina, O. L.; Arbuznikov, A. V.; Schimmelpfennig, B.;
Malkin, V. G. J. Comput. Chem. 2002, 23, 794; and references therein.
L32
Molecular Properties ’09 - Lectures
Optimized Gaussian Basis Sets for Molecular
Optical Property Calculations
Filipp Furche and Dmitrij Rappoport
University of California, Irvine, Department of Chemistry, Natural Sciences II,
Irvine, CA 92697-2025, USA
Basis set incompleteness is a key limitation in most large-scale electronic structure calculations of molecular optical properties such as linear and non-linear polarizabilities, vibrational Raman intensities, and electronic oscillator and rotatory
strengths. For systems containing more than 30–50 atoms, traditional diffuse augmented basis sets such as Dunning’s augmented correlation consistent basis sets
[1] or Sadlej’s basis sets [2] are often prohibitively expensive and plagued by linear dependence. To address this problem, a hierarchy of polarizability-optimized
basis sets was developed for atoms H–Kr that systematically approaches the basis
set limit of Hartree-Fock and density functional linear and non-linear molecular optical response properties. These basis sets were constructed by variational
optimization of atomic Hartree-Fock polarizabilities using analytical basis set gradients. We will show that the basis set convergence of optical properties can be
improved dramatically by adding few optimized polarization functions to Karlsruhe segmented contracted basis sets without an excessive increase of cost and
without introducing linear dependence.
References
[1] R. A. Kendall, T. H. Dunning, Jr., R. J. Harrison, J. Chem. Phys. 96 (1992),
6796.
[2] A. J. Sadlej, Theor. Chim. Acta 79 (1991), 123.
L33
Molecular Properties ’09 - Lectures
Optical activity of β, γ-enones in ground and excited state
Magdalena Pecula,b and Kenneth Ruudb
a)
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warszawa,
Poland
b) Department of Chemistry, Centre for Theoretical and Computational
Chemistry, University of Tromsø, N-9037 Tromsø, Norway
Circularly polarized luminescence (CPL) can be viewed as a counterpart
of electronic circular dichroism (ECD) in emisison spectroscopy. While
ECD is one of the methods used to probe chirality in ground electronic
state, CPL offers a possibility to probe chirality in excited state. When
the geometric structure of a molecule is similar in both states, the spectra
nearly overlap each other. However, there are molecules for which this is
not the case, including chiral cyclic β, γ-enones [1].
The selected members of this class of molecules have been studied by
means of linear response density functional and (for smaller systems)
coupled cluster methods. Geometry optimization has been carried out
for ground state and singlet 1 nπ ∗ excited state. ECD and CPL spectra
have been evaluated. The main purpose of the study is to elucidate the
source of remarkable sign reversal of ECD and CPL spectra of compounds
1 and 1a.
[1] P. H. Schippers, L. P. M. van der Ploeg, and H. P. J. M. Dekkers
J. Am. Chem. Soc. 1983, 105, 84-89.
L34
Molecular Properties ’09 - Lectures
Understanding the Raman optical activity spectra of polypeptides
with localized vibrations
Christoph R. Jacob, Sandra Luber, and Markus Reiher
ETH Zurich, Laboratorium für Physikalische Chemie, Wolfgang-Pauli-Strasse 10,
8093 Zurich, Switzerland
E-Mail: {christoph.jacob,markus.reiher}@phys.chem.ethz.ch
Raman optical activity (ROA), which measures the difference in Raman scattering between right- and left-circularly polarized light, is an important experimental technique for
studying the structure of biological molecules in aqueous solution. However, even though
a large number of ROA spectra, in particular of polypeptides and proteins, have been
recorded in the past decades, the experimental assignment of certain spectral signatures
to specific secondary structure elements remains uncertain in many cases, and quantum
chemical calculations are therefore necessary for a reliable assignment [1].
While efficient quantum chemical calculations of the ROA spectra of large polypeptides have recently become possible, such calculations provide a large amount of data and
the results are difficult to analyze. In particular for the vibrational spectra of polypeptides, a large number of close-lying normal modes contribute to each of the experimentally observed bands, which hampers the analysis considerably. This makes it difficult to
understand how the ROA spectra are affected by changes in the secondary structure.
To overcome these problems, we have developed a methodology for the analysis of
calculated vibrational spectra in terms of localized vibrations [2]. It is based on a transformation of the normal modes contributing to a certain band in the spectrum to a set of
localized modes. This is achieved by determining the unitary transformation that leads
to modes which are maximally localized with respect to a suitably defined criterion. We
demonstrate that these localized modes are more appropriate for the analysis of calculated
vibrational spectra of polypeptides and proteins than the normal modes, which are usually
delocalized over the whole system.
Here, we discuss how our analysis can be applied to rationalize the ROA spectra of
polypeptides and proteins. As a model system, a polypeptide consisting of twenty (S)alanine residues in the conformation of an α-helix and of a 310 -helix is considered. First,
we show how the use of localized modes facilitates the analysis of the positions of the
bands in the vibrational spectra, and how the total intensities of the bands in the parent
Raman spectra can be understood by considering representative localized modes [3]. In
addition we discuss how coupling constants between localized modes can be extracted and
how these coupling constants can be used to explain band shapes. Second, we proceed
to the analysis of the ROA spectra of the considered model peptides in terms of localized
modes, which provides a detailed picture of the generation of ROA bands in proteins [4].
[1] Ch. R. Jacob, S. Luber, M. Reiher, ChemPhysChem, 2008, 9, 2177.
[2] Ch. R. Jacob and M. Reiher, J. Chem. Phys., 2009, 130, 084106.
[3] Ch. R. Jacob, S. Luber, M. Reiher, J. Phys. Chem. B, 2009, in press,
DOI: 10.1021/jp900354g.
[4] Ch. R. Jacob, S. Luber, M. Reiher, in preparation, 2009.
L35
Abstracts
of
Posters
Molecular Properties ’09 - Posters
Polarization propagators: a powerful tool for both reliable calculations and the analysis of
NMR spectroscopic parameters on heavy and non-heavy atom containing molecules
Gustavo A. Aucar and Alejandro F. Maldonado
Institute of Modeling and Innovative Technology and Northeastern University of Argentina
Propagators are powerful theoretical tools that were first developed within the nonrelativistic
regime and applied to calculate atomic and molecular properties more than 30 years ago. Recent
relativistic generalization of polarization propagators has shown that they play a special role in
describing the quantum origin of some molecular properties and the broad implication of their
general definition.1
The theory of polarization propagators have: i) A formal definition that is the same for both
the NR and relativistic regime; ii) This definition can be related with the scattering amplitude of
QED; iii) Formal solutions of its equation of motion can be expressed in a perturbational scheme so
that they may be improved in a well-defined way; iv) Several implementations at different levels of
approach.
Within the NR regime SOPPA and SOPPA-CC calculations are between the most
reliables.2,3 Within the relativistic regime there appears several new understandings on the electronic
origin of magnetic properties. As an example, diamagnetism arise as a NR approximation. When
working within the relativistic regime one should be very careful in using well established NR
physical concepts like dia- and para- magnetic contributions.
In this presentation starting from a QED-based formulation of NMR spectroscopic
parameters (that gives solid grounds to the relativistic polarization propagator theory), we will show
recent calculations of such parameters for one, two- and more than two-heavy atom containing
molecules. We show that we only need to apply the UKB prescription with small enough basis sets
to get converged results of magnetic shieldings. We will also discuss briefly new applications of
polarization propagators to calculate and analyze proton transfer mechanisms on O---H---N systems
and predictions of J-couplings for F-F couplings of conjugated systems that can be used to build
quantum computers.
1. G. A. Aucar, Understanding NMR-J couplings by the theory of polarization propagators,
Concepts in Magn. Reson. Part A 32A, 88, 2008.
2. J. E. del Bene, I. Alkorta and J. Elguero, A systematic comparison of SOPPA and EOM-CC
J-couplings..., J. Chem. Theory and Comput. 4, 967, 2008.
3. T. Helgaker, M. Jaszunski and M. Pecul, The quantum-chemical calculations of NMR Jcouplings. Prog. in NMR Spectrosc. 53, 249, 2008.
P1
Molecular Properties ’09 - Posters
Implementation of high-order response functions with exchange-correlation
contribution and relativity
Radovan Bast, Andreas J. Thorvaldsen, and Kenneth Ruud
Center for Theoretical and Computational Chemistry (CTCC),
Department of Chemistry, University of Tromsø, N–9037 Tromsø, Norway
Ulf Ekström
Department of Theoretical Chemistry, Faculty of Sciences,
Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands
We present the implementation of atomic orbital-based response theory for one-, two- and
four-component relativistic Kohn–Sham models built on a quasienergy formalism [1–3]. The implementation consists of a stand-alone code that only requires the unperturbed density in the
atomic orbital basis as input, as well as a linear response solver by which we can determine the
perturbed density matrices to different orders, at each new order solving equations that have the
same structure as the linear response equation.
A high-order response code with exchange-correlation contribution requires high-order functional derivatives with respect to (spin) density (gradient) dependent variables. These functional
derivatives (to arbitrary order) are obtained by automatic differentiation of density functionals [4].
We present results of test calculations and check the validity and numerical stability against finite
difference results. Using automatic differentiation we are currently extending the response code to
accommodate magnetic and geometric perturbations to be able to treat a wide range of molecular
response properties in the two- and four-component relativistic framework.
[1] A. J. Thorvaldsen, K. Ruud, K. Kristensen, P. Jørgensen, S. Coriani, J. Chem. Phys. 129, 214108 (2008).
[2] R. Bast, A. J. Thorvaldsen, M. Ringholm, K. Ruud, Chem. Phys. 356, 177 (2009).
[3] Development version of DIRAC, a relativistic ab initio electronic structure program, Release DIRAC08 (2008),
written by L. Visscher, H. J. Aa. Jensen, and T. Saue (see http://dirac.chem.sdu.dk).
[4] U. Ekström, R. Bast, A. J. Thorvaldsen, L. Visscher, K. Ruud, manuscript in preparation.
P2
Molecular Properties ’09 - Posters
CHEMICAL CHARACTERIZATION OF SUPERHEAVY ELEMENTS ON GOLD CLUSTERS BY 4­COMPONENT FULL RELATIVISTIC DFT. Leonardo Belpassi, Loriano Storchi, Francesco Tarantelli, Antonio Sgamellotti, Harry M. Quiney
Dipartimento di Chimica e I.S.T.M.­C.N.R., Universita' di Perugia, 06123 Perugia, Italy
The chemical characterization of super heavy elements (SHE), achieved by studying their adsorption on a heavy metal surface, is currently of fundamental importance for the placement of new elements in the periodic table [1]. Relativistic effects on SHE chemistry are known to alter expectations dramatically. We use full relativistic 4­component Dirac­Kohn­Sham (DKS) theory in order to gain an accurate understanding of the chemical properties of the element 112 (E112) bound to several gold cluster and extend this approach to the next candidate to experimental characterization: E114. Cluster calculations, analyzing the energetics and electronic structure of the interaction, and assessing convergence with respect to the basis set size and number of atoms have been carried out using the full relativistic density functional theory code BERTHA[2]. The large numbers of heavy atoms that need be considered, the peculiar structure in the DKS calculations and the large basis set adopted required an extreme computational effort, demanding the development and implementation of highly effective parallelization scheme. The parallelization has been performed using MPI and ScalaPack. One peculiar aspect of our approach is that only the master process needs to allocate all the arrays, that is the DKS matrix, the overlap matrix and eigenvectors one. Each slave process allocates only some temporary small arrays when needed. Using such new parallel implementation of the DKS method, we have been able to compute accurately the electronic structure and interaction energy of E112 and E114 with several gold clusters up to Au34. The chemical characterization of these SHE has been carried out comparing the energetics, electronic structure and charge transfer (see the above picture) with the results obtained for their homologues Hg and Pb and the inert noble gas atom Rn. All the calculations (i.e. 350K CPU hours) have been performed, within the DECI project, on the SGI Altix 4700 at Leibniz­Rechenzentrum (LRZ) – Germany. [1] Schädel M., Angew. Chem. Int. Ed. 2006, 45, 386. Eichler, R. et al. , Nature 2007, 447, 72.
[2]BERTHA, H. M. Quiney, H. Skaane, and I. P. Grant, Adv. Quantum Chem., 32, 1(1999). L. Belpassi, F. Tarantelli, A. Sgamellotti, and H. M. Quiney, Phys. Rev. B, 77, 233403 (2008).
P3
Molecular Properties ’09 - Posters
Molecular Dynamics Simulations of Cs+@C60 Impact Formation
V. Bernstein and E. Kolodney
Department of Chemistry, Technion-Israel institute of Technology, Haifa 32000, Israel, e-mail:
[email protected]
Recently the yields of cesium-fullerene endohedral ions, [Cs@C60]+, were measured
under field-free conditions, following the collision of cesium ions with a nearmonolayer of fullerene molecules adsorbed on a gold surface [1]. The current work
deals with molecular dynamics simulations of the implantation process and yields of
Cs+ ion insertion into a free fullerene molecule, fullerene dimer, and fullerene molecule
absorbed on a gold surface (the last two are considered as supported fullerene
configuration) [2]. The simulations were carried out for impact energies (35-150 eV),
which are similar to those used in the Cs+ ion beam-surface experiments [1]. A number
of possible routes for the collisional interactions of alkali ion with the fullerene
molecule were identified by analyzing the collision trajectories as a function of impact
energy. We discuss the energy transfer, the yield of endohedral complexes, and the
implantation mechanisms as a function of impact energy for both free and supported
fullerene molecule. The relative yields of endohedral complexes as a function of impact
energy (35-150 eV) were calculated and found to be comparable with the
experimentally measured yields for a surface adsorbed fullerene. A unique off-center
(“slip-through”) penetration and trapping mechanism at near threshold energies ( ≤ 50
eV) was observed. There is a clear trend for increased survival probability of the
endohedral complex with an increase in the impact parameter for implantation. The
direct collision-induced fragmentation is characterized by a very large amount of
collisional energy that is transferred directly from Cs+ to a small moiety of the C60
molecular cage.
We have found pronounced supporter effects, which are manifested by the
endohedral yield and the mechanism of penetration. The supporter effect increases with
the increase in the collision energy and the mass of the energy absorber. This effect
influences the shape of the impact energy dependent yield mainly in terms of its
maximum value and the high-energy tail. The shape of the calculated yield curve is
approaching the experimental one, the maximum of the yield is shifted towards 85 eV,
which is quite close to the experimental measurements and the high energy tail is
decaying more slowly. For the low energy side the mechanism of Cs+ ion implantation is
mostly not altered by the impacts of Cs+ ion with either non-supported or supported
fullerene molecule. Kinetic energy distributions (KEDs) of the outgoing endohedral
complex Cs+@C60 were calculated and were found to be comparable with the
experimentally measured ones.
With regard to the endohedral yield, we conclude that the low energy side of the
impact energy dependent yield curve is rather insensitive to the support effect. This is
attributed to the ultra-fast, sub-picosecond penetration event, controlling the yield at low
energy collisions, where energy transfer to the supporting species (another fullerene
molecule or a solid substrate) is negligible on the time scale of the actual
penetration/trapping process.
[1] A. Kaplan, Y. Manor, A. Bekkerman, B. Tsipinyuk, and E. Kolodney, a) J.Chem.Phys.,
120, 1572 (2004); b) Int. J. Mass Spectr, 228, 1055 (2003); c) Ibid., 249/250, 8 (2006).
[2] V. Bernstein, E. Kolodney. To be submitted.
P4
Molecular Properties ’09 - Posters
The COSTMAP initiative:
data mining of molecular information from a graph-based database
Stefano Borini, Hans Peter Lüthi
ETH Zürich, Switzerland
Abstract
With the recent increase of available computational power, and the efficient sharing of this resource
among research centers, high-throughput calculation of molecular properties is becoming more and
more feasible. Data from different computations and different research groups could then be
aggregated in databases of molecular structures, where each configuration can be decorated with
QM-evaluated properties, data relationships, and user-generated metainformation in the form of
annotations, comments and peer-review evaluation.
Sensible and positive proof exist that this concept is solid and produces added value for the user
community: examples can be found in community-driven web databases such as Wikipedia, in
bioinformatic databases for genomic and clinical information, and in structural databases like the
Cambridge Structural Database. At the moment, however, the quantum chemistry community is
missing a standard, public access database to share scientific knowledge and easily infer structureproperty relationships.
The talk will present the COST Molecular Annotation Project (COSTMAP), a prototype database
implemented at ETH Zurich, soon to be integrated with the Lensfield project, developed in Peter
Murray-Rust' group at Unilever Center, Cambridge, UK.
COSTMAP employs a graph-based data model to store, retrieve and represent information about
molecules. When fully operative, the database will allow user-friendly search and retrieval of
molecular structures both from the web and via scripting. Search criteria will be based on structural
features, property values and user-produced annotations. Standard data formats, such as CML, RDF,
and Q5Cost will be used throughout the implementation for maximum interoperability. The
database backend code will be released under an open source license, allowing any research group
to deploy “research-field dependent” databases, and the creation of a federated, scalable information
network. COSTMAP is part of a larger initiative for the development of a python toolkit for
quantum chemistry scripting, TheoChemPy.
P5
Molecular Properties ’09 - Posters
The photoelectron spectrum of ammonia, a test case for the calculation
of Franck-Condon factors in molecules undergoing large geometrical
displacements upon photoionization
Andrea Peluso, Raffaele Borrelli, and Amedeo Capobianco
University of Salerno, Italy, Department of Chemistry
The vibrational structure of the photoelectron spectrum of ammonia, the simplest
molecule undergoing a large displacement of its equilibrium geometry upon
photoionization, is analyzed by evaluating the Franck-Condon integrals at anharmonic
level of approximation. It is shown that if the rectilinear Cartesian representation of
normal modes is adopted, Duschinsky’s transformation yields a too large displacement of
the bond distance coordinate, with the appearance of several progressions which are not
observed in the experimental spectrum. This apparent failure is completely corrected by
the inclusion of anharmonic couplings between the real active mode, the out of plane
bending of the planar cation, and the totally symmetric stretching mode, leading to an
excellent reproduction of the observed spectrum, see figure 1, and to a more convincing
assignment of the weaker progression observed in the high resolution spectrum.
Figure 1. (­) Franck­Condon factors computed by using the Cartesian coordinate representation of normal modes and the anharmonic potential energy () experimental data.
P6
Molecular Properties ’09 - Posters
Four-component Relativistic Theory for NMR Parameters
Lan Cheng, Yunlong Xiao and Wenjian Liu*
Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular
Engineering, Peking University, Beijing 100871
NMR parameters[1] are intrinsically relativistic all-electron properties and therefore
require in principle a fully relativistic treatment[2]. Recently several schemes[3-6] have
been proposed to incorporate the magnetic balance (MB) in the four-component
relativistic calculations. Conceptually, the diamagnetism is recovered naturally and
correct nonrelativistic limit can be obtained with a finte basis set. Computationally,
the heavy demand on the basis set can be greately alleviated.
In this poster first it is shown[7] that all these methods can be understood as the
decomposition of the first order wave function into a magnetic part known from the
zeroth order calculation and a residual that can be effectively expanded in terms of the
regular basis sets. Thus the basis set requirement can be greatly reduced. It is shown
via extensive calculations of Rn+85 and Rn that all these methods lead to a compact
expansion of the perturbed wave function and perform similarly. Further,
magnetically balanced gauge including atomic orbital (MB-GIAO) method[8] has been
introduced to overcome the gauge origin problem in the four-component molecular
calculations of NMR shielding tensors, where the gauge origins of both the
Hamiltonian and the magnetic balance conditions are distributed among the individual
atomic orbitals. Pilot molecular applications have been carried out within the coupled
perturbed Dirac-Kohn-Sham (CP-DKS) framework. It is shown that the calculated
NMR shielding tensors are independent of the choice of gauge origin and the rapid
basis set convergence can be achieved. It is also found that the negative energy states
(orbitals) are only important for the description of the first-order core orbitals. As
such, their contributions to the paramagnetism are essentially transferrable and
irrelevant for chemical shifts. Finally, it should be emphasized that the formalism can
be extended to wave function based methods in a straightforward manner.
References:
1. N. F. Ramsey, Phys. Rev. 78, 699 (1950); 83, 540 (1951); 86, 243 (1956).
2. P. Pyykkö, Chem. Phys. 22, 289 (1977).
3. W. Kutzelnigg, Phys. Rev. A. 67, 032109 (2003).
4. Y. Xiao, W. Liu, L. Cheng, and D. Peng, J. Chem. Phys. 126, 214101 (2007).
5. Y. Xiao, D. Peng, and W. Liu, J. Chem. Phys. 126, 081101 (2007).
6. S. Komorovsky, M. Repisky, O. L. Malkina, V. G. Malkin, I. M. Ondik and M.
Kaupp, J. Chem. Phys. 128, 104101 (2008).
7. L. Cheng, Y. Xiao, and W. Liu, J. Chem. Phys. 130, 144102 (2009).
8. L. Cheng, Y. Xiao, and W. Liu (to be published).
P7
Molecular Properties ’09 - Posters
S. Coriania, T. Kjærgaard, P. Jørgensen, A. Thorvaldsen, K. Ruud, R. Berger
a
Dipartimento di Scienze Chimiche, Università degli Studi di Trieste, Italy, and Centre for Theoretical
and Computational Chemistry, University of Oslo, Norway
Title
In silico determination of optical and spectroscopic properties: a few recent
methodological and applicative results
Abstract
Recent methodological and applicative achievements in the area of the ab initio
computational determination of molecular response properties and related optical and
spectroscopic phenomena will be presented, including for instance studies of
magnetic circular dichroism and of the vibronic fine structure in the absorption
spectrum of various molecular species.
P8
Molecular Properties ’09 - Posters
First-Principles Studies of Optical Rotation and Circular Dichroism Spectra
T. Daniel Crawford
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, U.S.A
[email protected]
The interaction of chiral molecules with polarized light (both in absorption and refraction) may be
used to determine the “handedness” of an enantiomerically pure sample, provided sufficient details about the corresponding circular dichroism and birefringence are known a priori. The theoretical prediction of such properties, however, is a difficult task because of their delicate dependence on a variety of intrinsic and extrinsic factors, including electron correlation, basis set, vibrational/temperature effects, solvent, etc.1,2 Over the last several years, our group has investigated the
ability of state-of-the-art coupled cluster methods to provide accurate and reliable chiro-optical properties such as optical rotation and circular dichroism spectra, and this talk will discuss our recent
progress in this area.3 In particular, we will the current capabilities of ab initio response methods for
predicting gas-phase optical activity, the impact of molecular vibrations,4,5 and recent advances in
our understanding of the structural underpinnings of optical activity.
1 T.D.
Crawford, Theor. Chem. Acc. 115, 227-245 (2006).
Pecul and K. Ruud, Adv. Quantum Chem. 50, 185-212 (2005).
3 T.D. Crawford, M.C. Tam, and M.L. Abrams, J. Phys. Chem. A 111, 12057-12068 (2007).
4 T.B. Pedersen, J. Kongsted, T.D. Crawford, and K. Ruud, J. Chem. Phys. 130, 034310 (2009).
5 T.D. Crawford and W.D. Allen, Mol. Phys., in press.
2 M.
P9
Molecular Properties ’09 - Posters
THE SECOND-ORDER MAGNETIC AND ELECTRIC PROPERTIES OF RGH+ CATIONS
Janusz Cukras, Andrej Antušek, Filip Holka, Joanna Sadlej
Laboratory of Intermolecular Interactions, Faculty of Chemistry, University of Warsaw,
Pasteura 1, 02-093 Warsaw, [email protected]
The RgH+ series of noble-gas hydride cations serves as an interesting model to
investigate the influence of relativistic and correlation effect on the molecular
properties. The shielding constants, σ, spin-spin coupling constants, J, polarizabilities,
α, and first hyperpolarizabilities, β, for RgH+ cations have been calculated (σ, J, β for
the first time) using the non-relativistic and relativistic approach. The relativistic effect
has been included using the full four-component Dirac-Hartree-Fock method in case of
the magnetic properties and the Douglas-Kroll method in case of electric properties. The
influence of the relativistic and correlation effects is analyzed. The values of σ and α
parameters increase with the atomic number. The influence of the relativistic and
correlation effect is opposite[1,2].
1 Janusz Cukras, Joanna Sadlej, ''Predicted NMR properties of noble gas hydride cations RgH+'',
Chemical Physics Letters, Volume 467 (2008), s. 18-22.
2 Janusz Cukras, Andrej Antušek, Filip Holka, Joanna Sadlej, ''Static electric polarizabilities and first
hyperpolarizabilities of molecular ions RgH+ (Rg=He, Ne, Ar, Kr, Xe): Ab initio study'', Chemical
Physics Letters, in press.
P10
Molecular Properties ’09 - Posters
Benchmark calculations of the nuclear quadrupole moments in heavy
atomic systems .
Ephraim Eliav, Hana Yakobi, Igor Itkin and Uzi Kaldor.
School of Chemistry, Tel Aviv University, 69978 Tel Aviv, Israel
The relativistic multi-reference Intermediate Hamiltonian Fock-space coupled
cluster method is employed to compute the electric field gradients (EFG) on the
nuclear of the atomic gold [1], lanthanum, hafnium and the halogens atoms [2] using
the finite-field approach. Combined with the experimental nuclear quadrupole
coupling constants (NQCCs) they yield the highly accurate nuclear quadrupole
moments of the elements. Calculations were made using the Dirac04 [1] program.
References:
1. Yakobi, Hana; Eliav, Ephraim; Visscher, Lucas; Kaldor, Uzi., J.Chem. Phys.,
(2007), 126(5), 054301
2. Yakobi, Hana; Eliav, Ephraim; Kaldor, Uzi , J.Chem. Phys (2007), 126, 184305
3. "Dirac, a relativistic ab initio electronic structure program, Release DIRAC04.0
(2004)", written by H. J. Aa. Jensen, T. Saue, and L. Visscher with contributions from
V. Bakken, E. Eliav, T. Enevoldsen, T. Fleig, O. Fossgaard, T. Helgaker, J. Laerdahl,
C. V. Larsen, P. Norman, J. Olsen, M. Pernpointner, J. K. Pedersen, K. Ruud, P.
Salek, J. N. P. van Stralen, J. Thyssen, O. Visser, and T. Winther.
(http://dirac.chem.sdu.dk)
P11
Molecular Properties ’09 - Posters
Photochemical properties of Ir and Pt organometallic
complexes.
Daniel Escuderoa) and Leticia Gonzáleza)
a) Institut für Physikalische Chemie, Friedrich-Schiller Universität, Jena, Germany
Light-activation processes in organometallic complexes are a promising field with
strong applications in artificial photosynthesis, dye sensitized solar cells and selective
bond activation. Generally, light-harvesting antenna complexes are activated through
high-absorbing low-lying MLCT states that undergo efficiently intersystem crossing to
3
MLCT states, which feature lifetimes of microseconds. Effective phosphoresce
emission can be achieved from these 3MLCT states, as e.g. in Ir cyclometalated
complexes, making them best candidates as photoactive systems in light emitting diodes
technology.
To get an insight into the photophysical properties of systems of more than one hundred
atoms, state of the art calculations involve the use of DFT theory and its time-dependent
(TD-DFT) version. In particular, we have investigated:
i)
Several Pt complexes, which serve as model systems for selective lightcatalyzed C-C bond activation[1]. We have evaluated the steric/electronic
influences of several substituents on the photophysical properties and
consequently on the photochemical reactivity[2]. Both steric and electronic
play a major role on the selective C-C bond activation.
ii)
Some heteroleptic Ir cyclometalated complexes. In a joint experimental and
theoretical effort[3] we have evaluated the effects of the phenyl-1H[1,2,3]triazole cyclometalating ligand towards achieving blue emission. A
fairly good agreement is observed between the experimental and theoretical
absorption spectra when considering solvent effects and using a hybrid
functional. Furthermore, several theoretical strategies have been considered
to reproduce the experimental phosphorescence emission maxima.
[1] Petzold, H.; Weisheit, T.; Görls, H.; Breitzke, H.; Buntkowsky, G.; Escudero, D.;
González, L.; Weigand, W. Dalton Trans., 2008, 1971
[2] Escudero, D.; Assmann, M.; Pospiech, A.; Weigand, W.; González, L. Phys. Chem.
Chem. Phys, 2009, DOI:10.1039/B903603B
[3] Beyer, B.; Escudero, D.; Ulbricht, C.; Friebe, C.; Winter, A.; Schubert, U.;
González, L. Organometallics., 2009, submitted
P12
Molecular Properties ’09 - Posters
A QM/MM//MD MODEL FOR THE COMPUTATION OF AQUEOUS NITROXIDE
HYPERFINE COUPLING CONSTANTS
C. Houriez, a M. Masella, b S. Queyroy, a D. Siri, a N. Ferré a
Laboratoire Chimie Provence, Chimie Théorique,Université de Provence, Marseille, France.
B
Laboratoire Chimie du Vivant, CEA, Saclay, France.
E-mail: [email protected]
a
The development of a sequential molecular dynamics + hybrid quantum mechanics/molecular
mechanics (QM/MM//MD) approach is presented and it is applied to the evaluation of some
hyperfine coupling constants (hcc) of small nitroxides solvated in water[1,2]. This model relies
on a sophisticated polarizable forcefield featuring a many-body hydrogen bond potential[2],
whose parameters have been carefully fitted to QM calculations with special attention paid to the
nitrogen out-of-plane angle. It involves also an electronic embedding of the QM subsystem
thanks to the ElectroStatic Potential Fitted (ESPF) operator method [3], able to take into account
the instantaneous electrostatic anisotropy of the solvent. Our recent results will demonstrate the
accuracy and the statistical relevance of the method, allowing a direct comparison of the
computed mean hcc values with the experimental data. The discussion will focus on the solvent
contribution to hcc which seems to be almost constant whatever nitroxide is considered and is
rationalized as a competition between the local hydration structure and the bulk effect[4].
References:
[1] Houriez, C.; Ferré, N.; Masella, M. & Siri, D. J. Chem. Phys., 2008, 128, 244504
[2] Houriez, C.; Ferré, N.; Masella, M. & Siri, D. J. Molec. Struct (Theochem), 2009, 898, 49
[3] Masella, M. Mol. Phys., 2006, 104, 415
[4] Ferré, N. & Ángyán, J. G. Chem. Phys. Lett., 2002, 356, 331
[5] Houriez, C.; Ferré, N.; Siri, D. & Masella, M. submitted to J. Phys. Chem. B
P13
Molecular Properties ’09 - Posters
High order properties by solving equation of motion of first order
reduced density matrix in Hartree-Fock or density functional
theory using perturbation- and time-dependent basis sets
Bin Gao,1 Jun Jiang,2 Ying Zhang,2 Radovan Bast,1
Andreas Thorvaldsen,1 Kenneth Ruud,1 and Yi Luo2
1
Centre for Theoretical and Computational Chemistry (CTCC),
Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway
2
Department of Theoretical Chemistry, School of Biotechnology,
Royal Institute of Technology, SE-10691 Stockholm, Sweden
(Dated: May 3, 2009)
Abstract
High order properties of systems have been discussed by solving the equation of motion of
density operator (Liouville-von Neumann equation). Response functions (frequency domain) of
arbitrary operator are determined by the Fourier transformation or lter diagonalization of timedependent expectation value of the given operator. Practical methodology has been discussed in
the framework of Hartree-Fock and density functional theory by using the conception of reduced
density matrix, and special attention has been paid on using perturbation- and time-dependent
basis sets. Several numerical algorithms to approximate evaluation operator, such as exponential
midpoint rule, Magnus expansions, and Taylor expansions have been discussed.
1
P14
Molecular Properties ’09 - Posters
Theoretical investigation of new nucleation precursors in the
atmospheric SO2 oxidation
Núria González-García, Matthias Olzmann
Institut für Physikalische Chemie, Universität Karlsruhe (TH) und Karlsruher Institut für
Technologie (KIT), 76128 Karlsruhe, Germany
Sulfuric acid is an important aerosol precursor in the atmosphere [1]. It is formed from SO2
via the following sequence of homogeneous reactions [1, 2]:
SO2 + OH + M → HOSO2 + M
(1)
HOSO2 + O2 ⇔ HOSO4 → SO3 + HO2
(2)
SO3 + 2 H2O + M → H2SO4 + H2O +M
(3)
Recent experimental findings [3–5] strongly indicate that additional nucleation pathways
starting from HOSO4 but bypassing H2SO4 could be important. In this context, we have
examined the role of the HOSO4 + H2O reaction as a possible new starting point for
nucleation processes.
In our study, we calculated the energetic parameters of reactions (1) and (2), using very
high-level quantum chemical methods [6, 7]. The results confirm that reaction (2) is not a
direct reaction but indeed proceeds via an intermediate, the HOSO4 radical, which has a
relative energy of –71.4 ± 2.0 kJ/mol (at 0 K) with respect to the reactants. The
dissociation energy of HOSO4 towards SO3 + HO2 amounts to 62.9 ± 5.0 kJ/mol (at 0 K).
With these very reliable energies, a detailed characterization of the overall reaction (2)
in terms of a chemical activation mechanism was performed. We calculated energy and
angular momentum specific rate coefficients from first principles by using the Statistical
Adiabatic Channel Model. The pressure and temperature dependences were predicted by
solving a master equation with a step-ladder model for the transition probabilities.
The results show that the lifetime of the HOSO4 radical under atmospheric conditions
is too short for a bimolecular reaction with water to become important. The relative yield
of stabilized HOSO4, which can react with H2O, is negligible, and the situation does not
change either, when a bimolecular sink term for HOSO4 + H2O is included in the master
equation. The relative branching fraction of the HOSO4 + H2O channel is always below
1% at atmospheric conditions.
To summarize, our calculations show that the HOSO4 + H2O reaction is unlikely to
start additional nucleation pathways due to the short lifetime of HOSO4.
REFERENCES:
[1] B. J. Finlayson-Pitts, J. N. Pitts, Jr., Chemistry of the Upper and Lower Atmosphere, Academic
Press, San Diego 2000.
[2] W. R. Stockwell, J. G. Calvert, Atmos. Environ. 17, 2231 (1983).
[3] T. Berndt, O. Böge, F. Stratmann, J. Heintzenberg, M. Kulmala, Science 307, 698 (2005).
[4] T. Berndt et al., Atmos. Chem. Phys. 8, 6365 (2008).
[5] A. Laaksonen et al., Atmos. Chem. Phys. 8, 7255 (2008).
[6] W. Klopper, D. Tew, N. González-García, M. Olzmann, J. Chem. Phys. 129, 114308 (2008).
[7] N. González-García, W. Klopper, M. Olzmann, Chem. Phys. Lett. 470, 59 (2009).
P15
Molecular Properties ’09 - Posters
Molecular Properties 09
ESSENTIAL STATE MODELS FOR FUNCTIONAL MOLECULAR MATERIAL:
crossing the line between theory and experiment
Luca Grisanti, Cristina Sissa, Gabriele D'Avino, Francesca Terenziani ed Anna Painelli
Dipartimento di Chimica GIAF – Parma University e INSTM­UdR Parma
Abstract
==========
The low­energy spectral properties of π­conjugated molecules with electron­donor (D) and acceptor (A) groups is well described adopting essential state models for the electronic structure and accounting for the coupling between electrons and slow degrees of freedom, including molecular vibrations and polar solvation. These models can be adopted to rationalize the behavior of different families of compounds in a coherent reference frame. In particular essential two­state models properly not only describe the solvatochromism of polar (DA) chromophores, but rationalize subtle solvent effects on bandshapes in linear and non­linear optical responses as well as in time­resolved experiments. Similarly the anomalous solvatochromism shown by quadrupolar and octupolar dyes is accounted for as resulting from symmetry­breaking or localization phenomena in the excited states. Essential state models are semiempirical in nature and provide a natural bridge between theoretical approaches and experimental data. Relevant model parameters are obtained from a detailed analysis of optical spectra: the proper choice of diabatic molecular states allows the definition of a reliable set of environment independent molecular parameters, while and solvent effects are accounted for in terms of the solvent relaxation energy. This opens the way to the so called bottom­up modeling stategy where the information obtained from the analysis of solution spectra represents the basis to define models for molecular crystals, films or aggregates or, more generally, for materials where several molecules interact via electrostatic forces. To exemplify the power of the proposed approaches here we shortly address recent results in the definition of models for organometallic complexes of interest for NLO applications [1], and mixed­
valence compounds [2]. The bottom­up strategy is finally adopted to rationalize the coexistence of neutral and zwitterionic molecules in Fc­PTM crystals in terms of bistability induced by electrostatic intermolecular interactions [3].
[1] “Virtual charge­transfer in coordination complexes: a strategy to amplified two­photon absorption”, Luca Grisanti et al., submitted.
[2] “Essential State Models for Solvatochromism in Donor−Acceptor Molecules: The Role of the Bridge”, Luca Grisanti, Gabriele D’Avino, Anna Painelli, Judith Guasch, Imma Ratera and Jaume Veciana, J. Phys. Chem. B, 2009, 113 (14), pp 4718–4725.
[3] “Bistability in Fc­PTM Crystals: The Role of Intermolecular Electrostatic Interactions”, Gabriele D’Avino, Luca Grisanti, Judit Guasch, Imma Ratera, Jaume Veciana and Anna Painelli, J. Am. Chem. Soc., 2008, 130 (36), pp 12064–
12072
P16
Molecular Properties ’09 - Posters
EVV 2DIR spectroscopy: determination of intermolecular geometry
via electrical anharmonic couplings
Rui Guo, Frederic Fournier, Paul M. Donaldson, Elizabeth M. Gardner,
Ian R. Gould, and David R. Klug
Department of Chemistry, Imperial College London, London, SW7 2AZ, UK
When two molecules are brought close to each other, non-bonded interactions occur
between them. In particular, this may lead to couplings between their respective
vibrations, in the form of electrical anharmonicity. EVV 2DIR
(electron-vibration-vibration coherent two-dimensional infrared) spectroscopy is
inherently sensitive to this kind of couplings1,2. Ab initio calculations combined with a
simple dipole-dipole interaction model predict the appearance of new cross peaks in
EVV 2DIR spectra, generated entirely from interaction-induced electrical
anharmonicities. This was confirmed experimentally in the case of a two-component
liquid system, benzonitrile (BN) and phenylacetylene (PA), by the detection of
coupling cross-peaks between C ≡ C and C ≡ N stretching vibrations. Explicit
functional relationships connecting EVV 2DIR measurables to intermolecular
geometrical parameters were given. Distance and angles thus determined agree well
with theoretical predictions for BN-PA system3. Implications of this approach for the
study of interacting chemical groups in more complicated systems and subsequent
possible applications will be discussed.
Fig. 1. Theoretical EVV 2DIR spectra for BN (left), PA (centre) and
Fig. 2. Experimental EVV 2DIR spectrum of 50%-50% mixture of
BN-PA dimer (right), experimental spectral regions were indicated by
BN and PA.
red squares.
1
F. Fournier, R. Guo, E. M. Gardner, P. M. Donaldson, C. Loeffeld, I. R. Gould, K. R. Willison, and D. R. Klug,
Acc. Chem. Res., submitted (2009).
2
P. M. Donaldson, R. Guo, F. Fournier, E. M. Gardner, I. R. Gould, and D. R. Klug, Chem. Phys., 350, 201 (2008).
3
R. Guo, F. Fournier, P. M. Donaldson, E. M. Gardner, I. R. Gould, and D. R. Klug, Phys. Rev. Lett., submitted
(2009).
P17
Molecular Properties ’09 - Posters
Formal oxidation states and realistic charge distributions in
transition metal chemistry
Johannes Hachmanna) and Garnet Kin-Lic Chana)
a) Department of Chemistry and Chemical Biology, Cornell University
Ithaca, New York 14853-1301, USA
The concept of oxidation states is one of the basic tools in chemistry and of particular
use for the classification of transition metal compounds: Based on the oxidation state of
the metal center in a complex, we conclude its number of d-electrons, and in turn
possible spin states, electronic d-d transitions between them, resulting coordination
geometries, reactivity, and other related properties. It is well known, that the assigned
integer charges of the oxidation states do not match the 'real charges' on the atomic
centers, and that the actual electron distribution will deviate notably from the formal
value.
We will address some of the consequences of the difference in the electron count,
like the implications on the concepts that build upon the oxidation state. We will
analyse, how to understand the electronic situation on the metal considering this
discrepancy, and how the experimental determination of oxidation states fits into this
situation.
P18
Molecular Properties ’09 - Posters
Atomic natural orbital basis sets from coupled-cluster wavefunctions
Michael E. Hardinga) and John F. Stantona)
a)
Center for Theoretical Chemistry, Department of Chemistry and Biochemistry
The University of Texas at Austin, Austin, Texas 78712, USA
New atomic natural orbital (ANO) basis sets are generated from various approximate
coupled-cluster wavefunctions. The contraction coefficients are defined by the natural
orbitals obtained from atomic valence-only coupled-cluster calculations while the exponents have been taken from Ref. [1]. Results obtained with the new basis sets, such as
Hartree-Fock and valence-correlation energies as well as selected molecular properties
are compared to those calculated with the original ANO basis set from Ref. [1], the uncontracted basis, and the corresponding valence sets of Dunning [2].
[1] J. Almlöf, P. R. Taylor, J. Chem. Phys., 86, 4070 (1987).
[2] T. H. Dunning, J. Chem. Phys., 90, 1007 (1989).
P19
Molecular Properties ’09 - Posters
Relaxed RI-MP2-F12 first-order properties
Sebastian Höfener and Wim Kloppper
Lehrstuhl für Theoretische Chemie,
Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
Christof Hättig
Lehrstuhl für Theoretische Chemie
Ruhr-Universität Bochum, D-44780 Bochum, Germany
Conventional wave function based methods use orbitals to represent the electronic wave function, which is not well suited to describe short-range electron correlation. Consequently, large
basis sets are required for high accuracy, making calculations very expensive. In the framework of F12 methods the wave function explicitly depends on the interelectronic distances in
the atom or molecule. This dependence dramatically improves the shape of the wave function
about the points where two electron coalesce and much more accurate results are obtained in
a given one-electron basis. In the past it has been shown that - as a rule of thumb - results of
quintuple-ζ quality can be achieved when modern F12 methods are applied using triple-ζ basis
sets.
We present our progress of the of RI-MP2-F12 gradients at the stage of relaxed first-order properties, implemented in the R ICC 2 program of the T URBOMOLE suite of programs for closed
and open shell molecules. Our implementation takes advantage of density fitting, a Slater-type
geminal (STG), the commutator approximation (in the spirit of approximation C) and Ansatz 2.
Due to prescreenings, such as numerical geometry optimizations, we found that it is sufficient
to apply approximation A and to assume the EBC when CABS singles are included. These provide a perturbative correction to Hartree-Fock and hence give a balanced description (in terms
of accuracy) of the Hartree- Fock reference and the correlation part.
We show that RI-MP2-F12/2*A is a valuable tool to compute highly accurate relaxed dipole
moments for medium-sized molecules and we expect an analogous behaviour for nuclear gradients, i.e. geometry optimizations.
References:
E. Kordel, C. Villani, W. Klopper, J. Chem. Phys 122, 214306 (2005)
W. Klopper, F. R. Manby, S. Ten-no, E. F. Valeev, Int. Rev. Phys. Chem. 25, 427 (2006)
P20
Molecular Properties ’09 - Posters
Deuteration effects on the enthalpy and entropy changes in encapsulation of
methyl-containing guest molecules in molecular cages:
Importance of the increase of internal rotation barrier
Suehiro. Iwata 1) Takeharu. Haino 2)
1) Tiyota Riken ([email protected]) 2) Univ. Hiroshima ([email protected])
Recently Haino and his coworkers succeeded in synthesizing a new self-assembling capsule which can
be a size- and shape-selective host for some organic molecules[Haino et al. Chem. Euro. J. 12, 3310, (2006)].
By using the competition equilibrium between the protiated and deuterated guest molecules in the encapsulation reactions, they determined the temperature dependence of the ratio of the equilibrium constants KD/KH , and with the van’t Hoff plots, the isotope effects on the effective enthalpy change
ΔD-HΔHvH from the slope and the effective entropy change ΔD-HΔSvH from the intercept were determined. The obtained effects are enormous. The common character of all guest molecules is that all are
cylindrical long molecules having a methyl group at both ends. The methyl can interact with the
phenyl π electrons of the host molecule. Their findings are ①the ratio KD/KH is 1.17 ~ 1.35, ②The
slope ΔD-HΔHvH is negative, ③The intercept ΔD-HΔSvH is also negative, ④ΔD-HΔHvH(ΔD-HΔSvH) is not
correlated with ΔHvH(ΔSvH) for the corresponding the protiated guest molecule.
Because of the apparent large change in the entropy term, we can exclude the ordinal deuteration effect caused by the difference of the O-D and O-H vibration frequencies. The internal rotation levels
are sensible both to the inertia moment IX and to the barrier height of the rotor. The internal rotation
motions possibly induce the isotope effect on the encapsulation; by the encapsulation the barrier may
increase to VGAh from VGh. To examine the effects numerically, the internal rotation levels are solved
for a C3 potential energy curve of the barrier height Vh. Figure 1 shows the Vh dependence of the
quantum levels for CH3 and CD3. With a proper spin statistical weight for CH3 and CD3, the contribution Gir to the partition function from the internal rotation levels can be calculated. Because the van’t
Hoff plot (ln(KD/KH)=- ΔD-HΔG/RT) is used in the experimental analysis, the Vh dependence of the
Gibbs free energy Gir(Vh;CX3) is evaluated, and by taking the double difference {Gir(VGAh;CD3)Gir(VGAh;CH3)}-{ Gir(VGh;CD3)- Gir(VGh;CH3)}, the model van’t Hoff plot can be drawn for a given set
of (VGAh, VGh), and from the slope and intercept, ΔD-HΔHvH-ir and ΔD-HΔSvH-ir, are evaluated. Figure 2 is
the slope ΔD-HΔHvH-ir for (VGh+ΔVh, VGh) as a function of ΔVh for VGh=3, 5, and 9kJ/mol. The corresponding experimental values range from -1.96 to -3.75 kJ/mol; the figure demonstrates that the increase of the barrier height by the encapsulation explains semi- quantitatively finding ②. The calculated intercept ΔD-HΔSvH-ir is also negative, but much larger in absolute value than the corresponding
experimental data. By assuming only two lowest states (e0 and o1 in Fig.1), negative ΔD-HΔHvH-ir and
ΔD-HΔSvH-ir values result from the term (Vh)1/2(1/IX)1/2 in the Vh dependence of energy levels.
Fig. 1 The barrier height dependence of internal rotation levels of a
methyl group
P21
Fig.2 The calculated ΔD-HΔHvH as a
function of ΔVh=VGAh-VGh
Molecular Properties ’09 - Posters
Any-order imaginary time propagators for solving Schrödinger
equations
S. Janeceka) and E. Krotschecka)
a) Institute of Theoretical Physics, Johannes Kepler University, 4040 Linz, Austria
Low-lying eigensolutions of the Schrödinger equation can be efficiently computed using the diffusion method: A set of trial wave functions is evolved towards the eigensolutions of the Hamiltonian H by repeatedly applying the imaginary time evolution operator,
T (ε) = e−εH .
As the evolution operator is not known exactly, it is commonly approximated using
operator factorizations. Due to the diffusive character of the kinetic energy operator in
imaginary time, algorithms developed so far have been at most fourth order in the timestep ε. In previous work [1], we have shown that such fourth-order factorizations yield
a speed gain of one to two orders of magnitude when compared to conventional secondorder factorizations.
Here, we show that grid-based imaginary time propagation algorithms of any even
order in the time-step [3] can be devised by a recently developed multi-product splitting
scheme [2]. The convergence properties of such algorithms, up to the 24th order, are
demonstrated for two model systems: The three-dimensional harmonic oscillator, and a
simple (local potential) model of a C60 molecule. The efficiency of the algorithms is compared to conventional low-order factorization schemes as well as to the implicitly restarted
Lanczos method (IRLM). The implementation on parallel computer architectures is discussed.
[1] M. Aichinger, E. Krotscheck, Comput. Mater. Sci. 34, 188 (2005)
[2] S.A. Chin, arXiv:math.NA, 0809.0914 (2008)
[3] S.A. Chin, S. Janecek, E. Krotscheck, Chem. Phys. Lett. 470, 342 (2009)
P22
Molecular Properties ’09 - Posters
Manifestly gauge covariant density functional theory calculations in
strong magnetic fields
S. Janeceka) and E. Krotschecka)
a) Institute of Theoretical Physics, Johannes Kepler University, 4040 Linz, Austria
While ab initio electronic structure calculations in the absence of magnetic fields are
fairly standard nowadays, simulations involving strong magnetic fields are much less established, and a number of theoretical and methodological problems remain to be solved.
A key issue is to obtain gauge invariant numerical results for quantum-mechanical observables: In computer simulations, equations have to be represented on a finite-dimensional
basis set or on a numerical grid, and computational efficiency demands the number of basis functions or grid points to be small. This unavoidable truncation of the basis in general
destroys the correct gauge covariant behavior of Schrödinger-type equations, such as the
Kohn-Sham equations of density functional theory. As a consequence, a pronounced
gauge-dependent error of the eigenfunctions and eigenvalues is introduced. In the literature, the term gauge origin problem has been coined for this issue [1]. We present
a finite-difference representation of the Schrödinger Hamiltonian on real-space grids or
plane-wave bases that is manifestly gauge covariant, independent of the discretization and
the field strength [2].
While magnetic fields can usually be treated perturbatively on the molecular scale,
many interesting phenomena, such as the Aharonov-Bohm [3] and Quantum Hall [4] effects, can only be studied using methods that allow to go beyond the linear response
regime. It is known that the kinetic energy propagator in a uniform magnetic field can
be factorized exactly by using the analogy to the density matrix of the harmonic oscillator [5]. We have used this factorization to construct a class of diffusion algorithms for
computing eigensolutions of the Schrödinger equation in a magnetic field. The resulting
algorithms are exact for arbitrarily large homogeneous fields and comprise no computational overhead compared to the field-free case.
Applications of the above techniques to two different problem sets are presented: For
the low-field regime, we have calculated susceptibilities and nuclear magnetic resonance
(NMR) shifts of a representative set of molecules, and find satisfactory agreement with
experiment. In the high-field (i.e.: non-perturbative) regime, we we have performed simulations of quantum dots in strong magnetic fields.
[1]
[2]
[3]
[4]
[5]
T. Helgaker, M. Jazuński, K. Ruud, Chem. Rev. 99, 293 (1999)
S. Janecek, E. Krotscheck, Phys. Rev. B 77, 245115 (2008)
Y. Aharonov, D. Bohm, Phys. Rev. 115, 485 (1959)
K. von Klitzing, G. Dorda, M. Pepper, Phys. Rev. Lett. 45, 494 (1980)
M. Aichinger, S.A. Chin, E. Krotscheck, Comput. Phys. Comm. 171, 197 (2005)
P23
Molecular Properties ’09 - Posters
Information Theoretical Study of the Chirality of Enantiomers
Sara Janssens1, Alex Borgoo1, Christian Van Alsenoy2, Patrick Bultinck3, Paul Geerlings1
1
Free University of Brussels (VUB), Department of General Chemistry (ALGC), Pleinlaan 2,
1050 Brussels, Belgium
2
University of Antwerp (UA), Department of Chemistry, Universiteitslaan 1, 2610 Antwerp,
Belgium
3
Ghent University (Ugent), Department of Inorganic and Physical Chemistry, Krijgslaan 281
(S-3), 9000 Ghent, Belgium
[email protected]
In this work [1] we probed the Kullback-Leibler information entropy as a chirality
measure, as an extension of previous studies on molecular quantum similarity evaluated for
different enantiomers (enantiomers possessing two asymmetric centra in [2], with a single
asymmetric carbon atom in [3] and with a chiral axis in [4]). The entropy was calculated using
the shape functions of the R and S enantiomers considering one as reference for the other,
resulting in an information theory based expression useful for quantifying chirality. It was
evaluated for 5 chiral halomethanes possessing one asymmetric carbon atom with H, F, Cl, Br
and I as substituents. To demonstrate the general applicability, a study of two halogensubstituted ethanes possessing two asymmetric carbon atoms has been included as well.
Avnir’s Continuous Chirality Measure (CCM) [5] has been computed and confronted with the
information deficiency. By these means we quantified the dissimilarity of enantiomers and
illustrated Mezey’s Holographic Electron Density Theorem in chiral systems [6]. A
comparison is made with the optical rotation and with the Carbó similarity index.
As an alternative chirality index, we recently also calculated the information
deficiency in a way which is consistent with experiments as VCD spectroscopy and optical
rotation measurements. The entropy calculates the difference in information between the
shape function of one enantiomer and a normalized shape function of the racemate.
Comparing the latter index with the optical rotation reveals a similar trend.
[1] S. Janssens, A. Borgoo, C. Van Alsenoy, P. Geerlings, J. Phys. Chem. A 2008, 112,
10560.
[2] S. Janssens, C. Van Alsenoy, P. Geerlings, J. Phys. Chem. A 2007, 111, 3143.
[3] G. Boon, C. Van Alsenoy, F. De Proft, P. Bultinck, P. Geerlings, J. Phys. Chem. A
2006, 110, 5114.
[4] S. Janssens, G. Boon, P. Geerlings, J. Phys. Chem. A 2006, 110, 9267.
[5] H. Zabrodsky, D. Avnir, J. Am. Chem. Soc. 1995, 117, 462.
[6] P.G. Mezey, Mol. Phys. 1999, 96, 169.
P24
Molecular Properties ’09 - Posters
Excited state polarizabilities
Dan Jonsson
The Centre for Theoretical and Computational Chemistry
Universitetet i Tromsø
Department of Chemistry
9037 Tromsø, Norway
It is shown that the excited-state polarizability is related to the groundstate second hyperpolarizability. More precisely, the excited-state linear response function can be obtained from a double residue of the ground-state
cubic response function. This approach is particularly useful in density functional theory and coupled cluster theory, where, as a rule, an explicit representation of the excited state is not easily available. We describe some experiments related to excited-state polarizabilities and compare to calculations
at the density functional and coupled cluster level of theory, as implemented
in the Dalton program.
P25
Molecular Properties ’09 - Posters
TD-DFT Calculations on the Photophysics in Eu-Complexes
Johannes Kreutzer (1), Anne-Marie Kelterer(1), Fabian Niedermair(2), Karin Zojer(3),
Christian Slugovc(2), Egbert Zojer(4)
(1)
Institute of Physical and Theoretical Chemistry, (2) Institute of Chemistry and Technology of
Materials, (3) Institute of Theoretical Physics – Computational Physics, (4)Institute of Solid State
Physics, Graz University of Technology, A-8010 Graz, Austria
The wide range of application of light excitable optical emitting complexes of the type ML3
(M=transition metal, L=bidentate organic ligand comprising an extended pi-System) in OLED and
sensor technology is responsible for the current growth of publications and research efforts on this
topic. Especially the search for stable emitting materials covering the entire visible region becomes
increasingly important. Complexes with mixed quinolinolate-containing ligands have been identified as
promising materials, and also the lanthanide atoms, e.g. Europium, were subject of up-to-date research.
Upon illumination, the complexes are typically excited into the singlet state and by inter-system
crossing the excitation energy is transferred to the emitting triplet state of the Eu3+, which is mostly
independent of the ligands in such complexes. Until now, however, only a few reports of computational
studies on such lanthanide complexes can be found.
The main goal of the present study is to tune the singlet-triplet energy transfer in Eu(III)-quinolinolate
complexes (EuQ3) by using different electron pushing and pulling substituents in 5-position of the
ligands. In addition, the effect of different substitution positions within the Q ligand on the energy
transfer should be investigated.
Density Functional Theory (TD-B3LYP) is used for the investigation of the photophysics (in particular
the singlet and triplet excited states) of the involved ligands and Eu complexes. Europium is described
by large effective core potentials including the 4f electrons in the core, and the ligands are computed
with triple-zeta basis sets.
Absorption spectra of four hydroxyquinoline ligands were recorded and served
together with reference spectra [1] for evaluation of the theoretical method. The
degree of singlet-triplet splitting is influenced by the electron donating or
accepting character of the different substituents,
(e.g. R= -H, -OMe, -NH2, -CHO, -NO2, -CN,
-SO3, -Ph, -Py, -Me). Also the substitution
position (2, 3, 4, 5, 6 and 7) can shift the
energetic levels.
PL spectra of the Eu-quinolinolate complexes bearing -H, -NO2 and
-SO3 can been found in literature [2-4] and are used to benchmark
the data obtained from the calculations. The vertical excitation as
well as the singlet and triplet states were computed for one
symmetric and two chiral conformations describing different isomers
of a nearly octahedral Eu-complex.
The excitation process as well as the singlet triplet energy transfer
are explained theoretically with regard to the different substituents
on the hydroxyquinoline ligands, and conclusions about the possibility to tune the excitation towards
the visible spectrum are discussed.
[1]
[2]
[3]
[4]
e.g. D. Clarke et al., Monatshefte für Chemie 129 (1998) 419-422.
V. Tsaryuk et al., Journal of Photobiology A: Chemistry 177 (2006) 312-323.
P. M. Drozdzewski et al., Monatshefte für Chemie, 120(3) (1989) 187-190.
W.M. Watson et al., Inorganic Chemistry 14(11) (1975) 2675-2680.
P26
Molecular Properties ’09 - Posters
A modified preconditioned conjugated gradient
method for the computation of singular linear
response equations
Thomas Kjærgaard and Poul Jørgensen
Lundbeck Center for Theoretical Chemistry, University of Aarhus
8000 Århus C, Denmark
June 2, 2009
Several molecular response properties such as the Faraday B term of MCD, transistion
moment derivatives and Magnetochiral dichroism require calculations of singular linear
response equations of the form
(E[2] − ωf S[2] )b = B[1]
(1)
where the optical frequency matches an excitation energy ωf obtained as the eigenvalues
of the generalized hermitian eigenvalue equation
(E[2] − ωf S[2] )bf = 0
(2)
Rewriting the linear response equation in terms of the spectral representation clearly
shows the singluar nature of the equation.
X
b =
bg (ωg − ωf )−1 b†g + b−g (ωg + ωf )−1 b†−g B[1]
(3)
g
A standard response solver would therefore diverge. We present a modified preconditioned
conjugated gradient method where a central feature is a projector, which project out
any bf component and leaves only its orthogonal complement space. The right hand
side of the linear response equation B[2] must similar be projected to remove any S[2] bf
component and the linear response equations solved in the space orthogonal to the bf
component may be written as
Pf † E[2] − ωf S[2] Pf b = Pf † B[1]
(4)
This projected linear response equations are solved using an iterative procedure similar
to the linear scaling procedure of Ref. 1 , where trial vectors are added in pairs, thereby
retaining the structure of the E[2] − ωf S[2] in the reduced space equations, a strategy that
- for the eigenvalue problem - guarantees real eigenvalues and fast convergence.
1
Coriani, S.; Høst, S.; Jansı́k, B.; Thøgersen, L.; Olsen, J.; Jørgensen, P.; Reine, S.; Pawlowski, F.;
Helgaker, T.; Salek, P., J. Chem. Phys., 2007, 126, 154108.
1
P27
Molecular Properties ’09 - Posters
Author: Michal Kolář
Email: [email protected]
Place: Oslo, Norway
Date: 18th June 2009
Accurate determination of the structure of non-covalent phenol complexes
The determination of the structure of the non-covalent complexes represents a challenging
task of the recent theoretical chemistry. Two phenol moieties in the gas phase phenol
dimer are hold together via a hydrogen bond as well as via a dispersion interaction. Thus
the phenol dimer can be considered as a suitable model system for studying non-covalent
interactions.
Structure and stabilization energy of phenol dimer were determinated using various
quantum chemical ab initio methods and the results were compared with high-quality
spectroscopic data. The reliability of the ab initio methods together with recently developed DFT-D method was demonstrated.
In addition, the phenol· · ·methanol complex was further investigated.
P28
Molecular Properties ’09 - Posters
Quasienergy formulation of damped response theory
Kasper Kristensen, Joanna Kauczor, Thomas Kjærgaard, and Poul Jørgensen
In standard response theory [1] the excited states have infinite lifetimes. This leads to an
unphysical behavior for molecular properties in the resonance region, such as divergence of
dispersion curves and absorption spectra with infinitely narrow absorption peaks, i.e. stick
spectra. In damped response theory introduced by Norman et al. [2] these unphysical characteristics are avoided by modifying the Ehrenfest equation to include a damping term, which
effectively extends the domain of response functions to the complex plane. We present an
alternative quasienergy-based formulation of damped response theory, where phenomenological lifetimes of the excited states have been introduced in terms of complex excitation
energies. This leads to a set of (complex) damped response equations, which have the
same form to all orders in the perturbation. An implementation for solving the damped response equations in Hartree-Fock theory and Kohn-Sham Density Functional Theory within
a linear-scaling framework is presented. It is demonstrated that damped response theory
may be applied to obtain molecular absorption spectra in all frequency ranges, also for large
molecules, where the density of the excited states may be very high, and where standard
response theory is not applicable in practice.
[1] J. Olsen and P. Jørgensen, J. Chem. Phys. 82, 3235 (1985).
[2] P. Norman, D. M. Bishop, H. J. Aa. Jensen, and J. Oddershede, J. Chem. Phys. 123, 194103
(2005).
P29
Molecular Properties ’09 - Posters
Charge transfer in DNA
Effect of Dynamics and Environment
Tomáš Kubař, Marcus Elstner
Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig,
Hans-Sommer-Str. 10, 38106 Braunschweig, Germany
E-mail: [email protected]
Charge transfer (CT) in DNA has received much attention in the recent years due to
the role it plays in the oxidative damage and repair in DNA, and also due to possible
applications of DNA in nano-electronics. Despite intense experimental and theoretical effort the mechanisms underlying the long-range hole transport in DNA remain unresolved.
This is in particular due to the fact that CT depends sensitively on the complex structure
and dynamics of DNA as well as on the interaction with the solvent environment, which
could not be addressed adequately by the modeling approaches used up to now.
We have developed a multi-scale coarse-grained framework to simulate CT in DNA,
combining classical MD simulations and quantum-chemical calculations. The important
environmental effects are captured by means of a QM/MM coupling scheme, and the use
of the approximative DFT method SCC-DFTB makes the calculations significantly faster
compared to full DFT or wave-function methods. At the same time, accuracy is by no
means compromised, as proved by extensive testing and comparison to reference data.[1]
This methodology allows to analyze several factors responsible for hole transfer in
DNA, in detail.[2] The fluctuations of counterions and surrounding water lead to large
oscillations of site energies, which govern the energetics of CT. In contrast, the electronic
couplings depend only on DNA conformation and are not affected by the solvent.
CT along the DNA strand is simulated by the integration of time-dependent Schrödinger
equation within the coarse-grained DNA model, having cast the parameters obtained previously into the Hamiltonian. Such simulations directly probe the effect of the various
agents on the microscopic mechanism and rate of the transfer.[3] Our results emphasize
the importance of MD simulations in the study of hole transfer in DNA. Further, we
discuss the features of several CT mechanisms proposed recently.
Our current aim is to construct a self-consistent scheme to solve the dynamics of
both the molecular structure and the excess charge simultaneously. Here, the propagated
excess charge is projected onto the atoms of concerned nucleobases, and this will render
a realistic polarization of the environment (within the MD), which is often expressed in
terms of solvent reorganization energy.[4]
[1] T. Kubař, P. B. Woiczikowski, G. Cuniberti and M. Elstner, J. Phys. Chem. B 112
(2008) 7937–7947.
[2] T. Kubař and M. Elstner, J. Phys. Chem. B 112 (2008) 8788–8798.
[3] T. Kubař and M. Elstner: Solvent Fluctuations Drive the Hole Transfer in DNA –
a Coarse-Grained QM/MM Study, ms in preparation.
[4] T. Kubař and M. Elstner, J. Phys. Chem. B 113 (2009) 5653–5656.
P30
Molecular Properties ’09 - Posters
Effective Core Potential Basis Sets for Polarizability and
Hyperpolarizabilities
Henry A. Kurtz
Department of Chemistry
University of Memphis
Calculations of molecular polarizabilities require basis sets capable of accurately
describing the responses of the electrons to an external perturbation. Unfortunately, basis sets
that yield suitable quantitative results have traditionally been all electron sets with large
numbers of primitives, making their use computationally intractable even for moderately sized
systems. Existing effective core potentials basis sets can be systematically augmented to
provide results typically within 1% of large, all-electron basis sets for polarizabilities [J. Comput.
Chem. 26, 1464 (2005)]. Examples of this procedure will be shown along with results for main
group elements using a variety of methods. Application of these basis sets for transition metal
systems will be shown.
Applications for extended basis sets first and second hyperpolarizabilities for several
molecular systems will also be examined.
Acknowledgement: Coworkers on this project are Nick Labello (Univ. Minnesota
Supercomputer Institute) and Tony Ferriera (St. Jude Children’s Research Hospital)
P31
Molecular Properties ’09 - Posters
Analysis of the zero-field splitting in Cr(H2O)62+ through
multiconfigurational ab initio calculations.
D.G. Liakosa), D. Ganyushin a) and F. Neesea)
a) Institute of Theoretical and Physical Chemistry, University of Bonn, Germany
A detailed analysis of the value of Zero-Field Splitting for the divalent
chromium hexaquo complex is presented. The potential energy surface and all the
relevant parameters, for the Jahn-Teller active eg normal modes of vibrations, were
calculated through the use of state-averaged CASSCF calculations. Multiconfigurational
ab initio calculations, in the form of spectroscopy oriented configuration interaction,
SORCI, and difference dedicated configuration interaction, DDCI, were employed for
the calculation of the contributions to D at the minima of the surface. The total value
calculated for D in the SORCI level of calculation is found to be -2.45 cm-1 in excellent
agreement with the experimental estimate of -2.3 cm-1.
The contribution to D of direct spin-spin coupling has been calculated and the
result shows that it accounts for about 15% of the total value. The contribution of states
with S=1 is also studied and it is found that not only the lowest 3T1g triplets are
important for an accurate description.
Finally an evaluation of the accuracy of second order perturbation theory has
been performed and it has been found to be satisfactory.
[Insert Running title of <72 characters]
P32
Molecular Properties ’09 - Posters
Exact two-component Hamiltonians Revisited
Wenjian Liu and Daoling Peng
Institute of Theoretical and Computational Chemistry, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, P. R. China
Two-component relativistic Hamiltonians can be formulated in two conceptually
different ways:
Simple matrix formulation: One-step block-diagonalization of the Dirac matrix,
leading directly to algebraic exact two-component Hamiltonians (X2C).
Complicate operator formulation: First reducing the Dirac operator to a
two-component (analytic) operator and then constructing its matrix form.
Yet, a simple exercise of inserting the RI into the Foldy-Wouthuysen (FW)
Hamiltonian has led to the following observations:
(1) Both matrix and operator formulations of the same X2C Hamiltonians are simple
and equivalent.
(2) The dead FW Hamiltonian is revived and much simpler than other type operators
(ZORA, DKH, etc.)
(3) The development of X2C Hamiltonians “for electrons-only” has come to the end.
(4) Four-component and two-component are equally good! Neither “four-component
good, two-component bad” or “two-component good, four-component bad” makes
any sense.
P33
Molecular Properties ’09 - Posters
Relating Molecular Properties to Chemical Concepts: Electron Delocalization in
Linearly π-Conjugated Compounds and the Properties of Donor / Acceptor
Functionalized Polyacetylenes
Hans P. Lüthi, P. Limacher, K.V. Mikkelsen, and S. Borini
Even though a concept rather than an observable, electron delocalization is used to explain a
plethora of properties of π-conjugated compounds. In this work we investigate the (hyper-)
polarizability of donor/acceptor functionalized polyacetylenes as a function of chain length
and substitution pattern. We will also look at different types of polyacetylene chains
(“backbones”). The computed polarizabilities confirm much of the expected dependence of
this observable on the type of the substituents, but also reveal that large polarizabilities are by
no means reserved to classical push-pull substitution patterns. Furthermore, we will show how
the properties can be related to simple electron delocalization arguments [1,2].
The calculation of the polarizabilities was performed using a Coulomb attenuated density
functional theory method (CAM-B3LYP) along with linear response theory. The computed
data were archived in a prototype data repository, which greatly facilitated their analysis (see
also presentation of S. Borini).
[1] M. Bruschi, P. Limacher, J. Hutter, and H.P. Lüthi, JCTC, 2009, 5, 206-514.
[2] P. Limacher, K.V. Mikkelsen and H.P. Lüthi, JCP, in press.
P34
Molecular Properties ’09 - Posters
A Spin-adapted Size-extensive State-specific Multi-reference
Perturbation Theory (SS-MRPT) for Energy and Electrical
Properties
S. Maoa) , W. Liua) and D. Mukherjeeb)
a) Institute of Theoretical and Computational Chemistry, College of Chemistry and
Molecular Engineering, Peking University, Beijing 100871, P. R. China
b) Raman Center for Atomic, Molecular and Optical Science, Indian Association for the
Cultivation of Science, Kolkata 700032, India
The study of energy and the associated molecular properties of an electronic state
with pronounced and varying degrees of multi-reference character as a function of
molecular geometry in the entire region of molecular geometry remains a challenging
field. This is nontrivial due to the need of a balanced and proper description of both the
static and the dynamical correlation in the various geometries. The state-specific multireference perturbation theory (SS-MRPT) [1] appears to be a promising method in
PES study. It follows as a perturbative approximant of the full-blown state-specific
multi-reference coupled cluster theory, and shares with the parent method most of the
desirable property, e.g. it is rigorously size-extensive and is intruder-free in the whole
potential energy surface (PES), provided the target state energy is widely separated from
the energies of the virtual functions. In this poster, we will develop and apply the spinadapted SS-MRPT2 to calculate PES as well as electric dipole-moment and the
polarizability functions — the latter by using the finite field technique. The PES and the
property functions for several molecules, like HF, LiH, C2H4 and O3 will be presented.
From the behavior of the PES of these molecules, vis-à-vis highly accurate curves
obtained with the CI methods, the SS-MRPT2 affords an easy and reliable access to
both the PES and other molecular properties in situations with varying multi-reference
character.
[1] U.S. Mahapatra, B. Datta, D. Mukherjee, J. Phys. Chem. A., 103, 1822 (1999).
P35
Molecular Properties ’09 - Posters
On the Additivity of Current Density in Polycyclic Conjugated Hydrocarbons
Guglielmo Monaco* and Riccardo Zanasi
Dipartimento di Chimica, Università di Salerno, Via ponte Don Melillo, I-84084 Fisciano (SA), Italy
The interpretation of molecular properties in terms of additive - atomic, bond or orbital –
contributions has been a cornerstone for the development of chemistry and is a widespread tool in
experimental work. Magnetic molecular properties are not an exception as witnessed by well known
rules to recover them from additive atomic contributions. The discovery of large anisotropies of the
magnetizability in polycyclic conjugated hydrocarbons was early interpreted in terms of  currents.
Since then the  current density J– although not directly observed – has become a standard tool to
rationalize magnetizability and nuclear shieldings in these molecules. J can be described as
summation of ring or circuit currents, which, however, are not transferable from molecule to molecule.
In contrast with this usual non-transferability, an individual role of some non-overlapping moieties in π
networks has been sometimes invoked.1 Case studies for this investigation are coronenes: π systems,
formed by two concentric sp2-bonded annulenes. If the two annulenes were uncoupled, molecular
properties would be roughly given by the properties of the (properly charged) individual annulenes.
Among the molecular properties of these systems, considerable attention has been given to the J
tropicities on the two annulenes; indeed, these tropicities are expected to influence considerably the
NMR spectra. In effect, the interpretation of the NMR spectra of corannulene and its ions has been
performed in terms of the so-called annulene-within-an-annulene (AWA) model,2 but this model was
criticized considering its failure on neutral corannulene and other coronenes.3
As a more fundamental tool to interpret or even anticipate the J patterns, it is possible to recur
to the ipsocentric approach,3 which, however, ought to be refined in the study of corannulene dianion.4
According to the method, the successful application of the AWA model to corannulene2 seems
insufficient to assess that this system is a veritable AWA.5
As the AWA model is limited by the coupling of the annulenes, it can be expected to hold when
the linking bonds are fixed single bonds. This happens in the family of yet unsynthesized [2n,5]coronenes,6,7 and this fact has been used to design a novel closed-shell paramagnetic molecule.7 This
expectation holds equally well in other cases (but not in all cases) where the Kekulé count is
factorizable,8 in substantial agreement with known models.9
We will present a topological model of J, allowing a clear distinction of the behaviour of
[2n,5]-coronenes and corannulenes. The sum of purely rotational current density fields turn out to lead
to well distinguishable patterns of critical points. The novel use of topological models rather than the
mere a posteriori topological inspection of the maps has in our opinion a great potential for the
interpretation of magnetic properties.
1
Clar, E. The Aromatic Sextet, Wiley: London, 1972.
Baumgarten, M.; Gherghel, L.; Wagner, M.; Weitz, A.; Rabinovitz, M.; Cheng, P.-C.; Scott, L. T. J. Am. Chem. Soc. 1995,
117, 6254.
3
(a) Steiner, E.; Fowler, P. W. Chem. Commun. 2001, 2220–2221; (b) Steiner, E.; Fowler, P. W. J. Phys. Chem. A 2001,
105, 9553–9562.
4
Monaco, G.; Zanasi, R. Int. J. Quantum Chem. 2009, 109, 243-249.
5
Monaco, G.; Scott, L. T.; Zanasi, R. J. Phys. Chem. A 2008, 112, 8136-8147.
6
Monaco, G.; Viglione, R. G.; Zanasi, R.; Fowler, P. W. J. Phys.Chem. A 2006, 110, 7447–7452.
7
Monaco, G.; Fowler, P. W.; Lillington, M.; Zanasi, R. Angew.Chem., Int. Ed. 2007, 46, 1889–1892.
8
Monaco, G.; Zanasi, R. J. Chem. Phys. submitted.
9
Kuwajima, K. J. Am. Chem. Soc. 1984, 106, 6496; Haigh, R. B.; Mallion, C. W. Croat. Chem. Acta 1989, 62, 1; Randić,
M. Chem. Rev. 2003, 103, 3449.
2
P36
Molecular Properties ’09 - Posters
Mixed-Valence behavior
in Phtalocyanine-dimer cations
a
b
b
Antonio Monari , Stefano Evangelisti , and Thierry Leininger
a
Dipartimento di Chimica Fisica e Inorganica,Università di Bologna Viale Risorgimento 4, I-
40136 Bologna - Italy
b
Laboratoire de Chimie et Physique Quantiques, Université de Toulouse et CNRS,
118, Route de Narbonne, F-31062 Toulouse Cedex – France
Phtalocyanine compounds deserved a considerable interest in recent times,
particularly because of their possible use in the filed of nano-electronics [1,2].
In particular, the charge (in our case a hole) mobility in phtalocyanine stacked
arrangements has been recently investigated [3]. The present work is focused on
the ab-initio study of the hole-transfer mechanism between two monomers.
It is shown that the dimer exhibits a mixed-valence behavior if the distance
between the disks is larger than 3.5 bohr. The behavior is strongly dependent on
the relative angle θ between the disks. In particular, there are special values of θ
for which the excited state and the ground state have exactly the same energy,
thus implying the presence of a conical intersection.
[1] C. Piechocki et al., J. Am. Chem. Soc. 104, 5245 (1982).
[2] J. Tant et al., J. Phys. Chem. B 109, 20315 (2005)
[3] J. L. Brédas et al., Chem. Rev. 104, 4971 (2004)
P37
Molecular Properties ’09 - Posters
Recent Developments and Applications of Relativistic Model Core
Potentials for 1st-3rd Transition Metal Elements
Mori H.*1,2, Ueno-Noto K.1, Mon M. S.3, Tsukamoto S.3, Zeng T.4, Fujiwara T.5,
Soejima E.3, Osanai Y.6, Noro T.7, Klobukowski M.4, and Miyoshi E.2,3
1) Ocha-dai Academic Production, Division of Advanced Sciences, Ochanomizu University,
2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan
2) JST-CREST, Kawaguchi 332-0012, Japan
3) Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga Park,
Fukuoka 816-8580, Japan
4) Department of Chemistry, University of Alberta Edmonton, Alberta, Canada T6G 2G2
5) Faculty of Science, Rikkyo University, 3-34-1, Nishiikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
6) Faculty of Pharmaceutical Sciences, Aomori University, Aomori 030-0943, Japan
7) Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
In the last two decades, we have developed non-relativistic and relativistic model core
potentials (MCPs) accompanied by valence functions for atoms up to Rn [1-5]. The MCP
method, as well as the ab initio model potential (AIMP) method by Seijo et al. [6-9], is based on
the theory proposed by Huzinaga et al. and has the advantage of producing valence orbitals with
nodal structures over various other effective core potential (ECP) methods. The nodeless
pseudo-orbitals in the usual ECP approaches may produce a large exchange integral and thus
overestimate the correlation energies, resulting in excessive singlet–triplet splittings, for
example [10,11]. On the other hand, the valence orbitals with a nodal structure in the MCP
and AIMP methods can describe the valence correlation effects with reasonable accuracy. We
have recently shown for main group and transition metal elements that the valence correlation
effects can be described adequately by a combination of split MCP valence orbitals and
correlating contracted Gaussian-type functions.
We recently developed new MCP basis sets (spdsMCP) for the transition metal atoms,
where (n-1)s, (n-1)p, (n-1)d and ns electrons (n = 4,5,6 for 1st, 2nd and 3rd transition metals) are
treated explicitly [12-14]. These MCP data can be found on-line basis sets database,
http://setani.sci.hokudai.ac.jp/sapporo/Order.do. MCP integral and its analytical derivative
have already implemented in some quantum chemical program packages, GAMESS,
ABINIT-MP, and MOLCAS. In this presentation, we’ll introduce the MCP theory and discuss
the applicability to heavy elements’ chemistry by showing some application results containing
not only small diatomic molecules but also medium-large size systems containing heavy metal
elements.
References [1] Y. Sakai, E. Miyoshi, M. Klobukowski and S. Huzinaga, J. Comput. Chem. 8 (1987) 226. [2] Y.
Sakai, E. Miyoshi, M. Klobukowski and S. Huzinaga, J. Comput. Chem. 8 (1987) 264. [3] Y. Sakai, E. Miyoshi, M.
Klobukowski and S. Huzinaga, J. Chem. Phys. 106 (1997) 8084. [4] E. Miyoshi, Y. Sakai, K. Tanaka and M.
Masamura, J. Mol. Struct.: Theochem 451 (1998) 73. [5] Y. Sakai, E. Miyoshi and H. Tatewaki, J. Mol. Struct.:
Theochem 451 (1998), 143. [6] S. Huzinaga, L. Seijo, Z. Barandiaran and M. Klobukowski, J. Chem. Phys. 86
(1987), 2132. [7] L. Seijo, Z. Barandian and S. Huzinaga, J. Chem. Phys. 91 (1989) 7011. [8] Z. Barandiran, L.
Seijo and S. Huzinaga, J. Chem. Phys. 93 (1990), 5843. [9] Z. Barandiaran and L. Seijo, Can. J. Chem. 70 (1992)
409. [10] B. Pittel and W.H.E. Schwartz, Chem. Phys. Lett. 46 (1977) 121. [11] C. Teichteil, J.P. Malrieu and J.C.
Barthelat, Mol. Phys. 33 (1977) 181. [12] Y. Osanai, M. S. Mon, T. Noro, H. Mori, H. Nakashima, M.
Klobukowski, and E., Miyoshi, Chem. Phys. Lett. 452, 210 (2008). [13] Y. Osanai, E. Soejima, T. Noro, H. Mori,
M. S. Mon, M. Klobukowski, and E. Miyoshi, Chem. Phys. Lett. 463, 230 (2008). [14] H. Mori, K. Ueno-Noto, Y.
Osanai, T. Noro, T. Fujiwara, M. Klobukowski, and E. Miyoshi, Chem. Phys. Lett. submitted .
*Correspondence to H. Mori. (E-mail: [email protected], Tel: +81-3-5978-5068)
P38
Molecular Properties ’09 - Posters
Preliminary investigation of free base porphin using the full 24
orbital valence space
E. Neuscammana) , T. Yanaib), and G. K.-L. Chana)
a) Dept. of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 USA
b) Institute of Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
Free base porphin (FBP) poses a significant challenge to ab initio description due to
its multi-reference character and large valence space of 24 π orbitals. Previous studies
have been limited by the fact that traditional multi-reference methods such as complete
active space self consistent field theory (CASSCF) and complete active space second
order perturbation theory (CASPT2) typically cannot treat more than 16 valence
orbitals. By employing the new density matrix renormalization group theory with
orbital optimization (DMRG-SCF) and strongly contracted canonical transformation
theory (SC-CT), we treat both the static and dynamic correlation of FBP in the full
valence space. We present a description of how DMRG-SCF and SC-CT can be used
together to treat systems with large active spaces, as well as preliminary results for FBP.
[1] T. Yanai and G. K.-L. Chan, J. Chem. Phys., 124, 194106 (2006).
[2] T. Yanai and G. K.-L. Chan, J. Chem. Phys., 127, 104107 (2007).
[3] D. Ghosh, J. Hachmann, T. Yanai, and G. K.-L. Chan, J. Chem. Phys., 128, 144117
(2008).
[4] E. Neuscamman, T. Yanai, and G. K.-L. Chan, J. Chem. Phys., 130, 124102 (2009).
P39
Molecular Properties ’09 - Posters
NMR properties of heavy­metal complexes
Małgorzata Olejniczaka and Magdalena Pecul
University of Warsaw, Faculty of Chemistry
Pasteura 1, 02 – 093 Warsaw
e­mail: [email protected]
a
We present the relativistic calculations of NMR shielding tensors and spin­spin coupling constants in compounds exhibiting interesting intramolecular interactions and containing heavy metal atom. For this purpose, the iridium and rhodium compounds have been selected as models of such complexes: one group of compounds under study contained six­coordinated complexes of iridium, the second: four­coordinated complexes of iridium and the third: four­coordinated complexes of rhodium (see Figure 1 for examples). In all cases the scalar spin­spin coupling constants between interacting sites of molecule are of highest interest: in the first group the spin­spin coupling is transmitted through dihydrogen bonds (Ir – H ∙∙∙ H – N), in the other two groups ­ through hydrogen bonds of the M ­ H ∙∙∙ F type (M = Ir, Rh) and between atoms close in space for which the experimental spin­spin coupling constants are large (for instance 4J(PF), 4J(HF), 6J(HF)). As these sites are distant in a chemical sense, the substantial contribution to the spin­spin coupling originates from „through­space” mechanism. The chemical shifts and spin­spin coupling constants have been compared with experiment (whenever possible) and the agreement is satisfactory. The additional value of presented work is the discussion of proper methodology for the purpose.
Figure 1
Examples of structures of the systems under study.
P40
Molecular Properties ’09 - Posters
The charge transfer band of oxidized Watson-Crick
guanosine-cytidine complex
Amedeo Capobianco, Tonino Caruso, and Andrea Peluso
Dipartimento di Chimica, Università di Salerno,
I-84081, Fisciano, Italy
Email [email protected]
Abstract
The charge transfer transition of the one-electron oxidized Watson-Crick
complex between guanosine and cytidine derivatives has been observed for
the first time in the near IR region, by using spectroelectrochemical measurements in chloroform and dichloromethane solution. The assignment of the
spectroscopic signal has been performed by means of TDDFT computation.
This spectroscopic signal represents an important piece of information for a
deeper understanding of long range hole transport in duplex DNA, because
it provides the first experimental determination of the relative energy of the
electronic state with the positive charge localized on the cytosine site. These
electronic states are important, both because they determine hole transfer
rates via tunneling or superexchange mechanisms, and because DNA damages
at cytosine and thymine sites have been indeed observed, suggesting that the
higher energy electronic states with the positive charge partly localized on
pyrimidine sites are populated during hole migration.
1
P41
Molecular Properties ’09 - Posters
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P42
Molecular Properties ’09 - Posters
A new absolute
17
O NMR scale: rotational spectroscopy and
quantum chemical calculations
Cristina Puzzarini1 , Gabriele Cazzoli
Dipartimento di Chimica ”G. Ciamician”, Università di Bologna, I-40126 Bologna, Italy
Michael E. Harding2 , Jürgen Gauss
Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
The hyperfine structure (hfs) in the rotational spectrum of water containing
17
O has
been experimentally and theoretically investigated. From an experimental point of view,
the Lamb-dip technique has been employed for resolving the hfs due to spin-rotation
interactions of
17
O and H as well as the
17
O-H and H-H spin-spin interactions. The high
resolution of such a technique allowed us to obtain the hyperfine parameters to a very
good accuracy. The experimental determination has been supported by calculations at
the coupled-cluster level of the involved spin-rotation parameters, thereby focusing in
particular on a systematic study of the basis-set convergence and on vibrational effects.
The experimental isotropic
17
O spin-rotation constant has been used for determining the
paramagnetic part of the corresponding nuclear magnetic shielding constant, whereas the
diamagnetic contribution as well as zero-point vibrational and temperature effects have
been obtained in coupled-cluster calculations at the CCSD(T) level using large basis sets.
This joint procedure allows to establish a new absolute NMR scale for
17
O in favorable
agreement with pure theoretical predictions for the nuclear magnetic shielding of water.
1
2
Email : [email protected]
Present Address: Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry,
The University of Texas at Austin, Austin, Texas 78712, USA.
P43
Molecular Properties ’09 - Posters
Anharmonic vibrational calculations and the IET
spectrum of an adsorbed species on a metal surface
I. Respondek1 , D. M. Benoit1 , A. Tschetschetkin2 , B. Koslowski2 , A. Groß3
1 Theory
group – SFB 569, 2 Institute for Solid State Physics, 3 Institute for Theoretical
Chemistry
Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
We present an efficient and accurate computational scheme to calculate anharmonic vibrational frequencies of adsorbates on surfaces. We use the vibrational
self-consistent field method (VSCF), where we employ an iterative variational/perturbative scheme to correct for mode–mode correlation (VSCF/VCIPSI).1 The potential energy surface (PES) is generated on-the-fly using periodic DFT, where we
restrict the computation to only the relevant regions of the PES (fast-VSCF).2
We apply our methodology to compute the vibrational frequencies of the 4mercaptopyridine molecule on the Au(111) surface. The results are compared
with experimental inelastic electron tunneling (IET) spectra, which are obtained
using a low-temperature scanning tunneling microscope (STM-IETS). We also
compute the IET intensities using DFT calculations based on an extension of the
Tersoff-Hamann theory.3 We obtain an excellent agreement between theory and
experiment.
1
Y. Scribano, D. M. Benoit, Chem. Phys. Lett. 458, 384 (2008).
D. M. Benoit, J. Chem. Phys. 120, 562 (2004).
3
N. Lorente, M. Persson, Phys. Rev. Lett. 85, 2997 (2000).
2
P44
Molecular Properties ’09 - Posters
Correlated corrections for semiempirical methods.
Ground and excited states.
Piotr Rozyczko
Accelrys, Inc.
334 Cambridge Science Park
Cambridge
CB4 0WN
Abstract
Highly accurate calculations of the UV-Vis spectrum parameters based on the exact solution of the ground state SCF problem have been available for a long time
(MR-CI, CASSCF, EOM-CC), but these methods are very computationally intensive and therefore expensive. Basic correlated methods have also been available
with the semiemipirical ground state as CIS and CISD on top of NDDO or ZINDO
wavefunctions. The attractiveness of these methods is the speed at which the
calculations are performed, due to a very limited active space in which possible
electronic excitations are created.
Using a perturbational approach with an exponential wavefunction in form
of the coupled-cluster CC method alleviates both problems. The CC method,
when truncated at the double excitations level is a reasonably inexpensive (N 5 )
method, fully size consistent and providing a much better approximation to the
total correlation energy than the CI method with the same cost.
This presentation describes the use of EOM-CCD to evaluate excitation energies for a number of molecules. The accuracy of such combined approach is
generally good and the computational cost savings are sufficient to consider this
method an important tool for scientists targeting larger systems, intractable with
conventional ab initio approach.
1
P45
Molecular Properties ’09 - Posters
Effect of Spin-Orbit Coupling on Reduction Potentials of Octahedral Ruthenium
(II/III) and Osmium (II/III) Complexes
Martin Srnec, Jakub Chalupský, Michal Hocek, Mojmír Kývala, and Lubomír Rulíšek
Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic,
Flemingovo náměstí 2, 166 10 Praha 6, Czech Republic
Reduction potentials of several Ru2+/3+ and Os2+/3+ octahedral complexes - [M(H2O)6]2+/3+,
[MCl6]4-/3-, [M(NH3)6]2+/3+, [M(en)3]2+/3+ [M(bipy)3]2+/3+, and [M(CN)6]4-/3- - were calculated using
the CASSCF/CASPT2/CASSI and MRCI methods including spin-orbit coupling (SOC) by means
of first-order quasi-degenerate perturbation theory (QDPT).[1,2] It was shown that the effect of
SOC accounts for a systematic shift of approximately -70 mV in the reduction potentials of the
studied ruthenium (II/III) complexes and an approximately -300 mV shift for the osmium(II/III)
complexes. SOC splits the sixfold degenerate 2T2g ground electronic state (in ideal octahedral
symmetry) of the M3+ ions into the E(5/2)g Kramers’ doublet and G(3/2)g quartet, which were
calculated to split by 1354-1573 cm-1 in the Ru3+ and by 4155-5061 cm-1 in the Os3+ complexes. It
was demonstrated that this splitting represents the main contribution to the stabilization of the M3+
ground state with respect to the closed shell 1A1g ground state in M2+ systems. Moreover, it was
shown that the accuracy of the calculated reduction potentials depends on the calculated solvation
energies of both oxidized and reduced forms.[1,3] For smaller ligands, it involves an explicit
inclusion of the second solvation sphere into the calculations, whereas implicit solvation models
yield results of sufficient accuracy for complexes with larger ligands. In such cases (e.g.,
[M(bipy)3]2+/3+ and its derivatives), a very good agreement between the calculated (SOC-corrected)
values of reduction potentials and the available experimental values was obtained.[1,4] These
results led us to the conclusion that, especially for Os2+/3+ complexes, an inclusion of SOC is
necessary to avoid systematic errors of ~300 mV in the calculated reduction potentials.
References:
[1] Srnec, M.; Chalupský, J.; Fojta, M.; Zendlová, L.; Havran, L.; Hocek, M.; Kývala, M.; Rulíšek, L.: J.
Am. Chem. Soc. 2008, 130, 10947-10954.
[2] Srnec, M.; Chalupský, J.; Rulíšek, L.: Collect. Czech Chem. Commun. 2008, 73, 1231-1244.
[3] Jaque, P.; Marenich, A. V.; Cramer, C. J.; Truhlar, D. G. J. Phys. Chem. C 2007, 111, 5783-5799.
[4] Vrábel, M.; Hocek, M.; Havran, L.; Fojta, M.; Votruba, I.; Klepetářová, B.; Pohl, R.; Rulíšek, L.;
Zendlová, L.; Hobza, P.; Shih, I.; Mabery, E.; Mackman, R. Eur. J. Inorg. Chem. 2007, 1752-1769.
P46
Molecular Properties ’09 - Posters
The (2-pyridone)2 dimer and some observations about excitation
energy transfer
Espen Sagvolden
University of California, Irvine, Department of Chemistry, 1102 Natural
Sciences II, Irvine CA 92697-2025
The (2-pyridone)2 dimer has received much attention because it is regarded as a uracil dimer analog. Using TD-DFT we have computed excited
state structures. A reinterpretation of structures, spectroscopic data and
the size of the S1 /S2 splitting is proposed. A new minimum - a biradical is found in the S1 potential energy surface. The biradical appears to allow
for nonradiative transitions if the system attains this structure. The (2pyridone)2 structure is protected from the biradical structure by a barrier.
Vertical S1 /S2 splittings illustrate the charge transfer excitation problem of
hybrids and semi-local functionals in predicting the Davydov splitting. Direct integration of Förster’s expression for the excitation energy transfer rate
suggests that it is not well approximated by Davydov splittings.
1
P47
Molecular Properties ’09 - Posters
Complex polarization propagator calculations of magnetic circular dichroism spectra
Harald Solheim and Kenneth Ruud
Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway
Sonia Coriani
Dipartimento di Scienze Chimiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy and
Centre for Theoretical and Computational Chemistry, University of Oslo, P.O.Box 1033 Blindern, N-0315 Oslo, Norway
Patrick Norman
Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping, Sweden
The temperature-independent part of the magnetic circular dichroism spectrum is
conventionally divided into the Faraday A and B terms, where the A term is nonzero only for systems with degenerate states. We propose that this separation is
abandoned in favour of a unified temperature-independent term. The argument is
based on complex polarization propagator calculations of three structurally similar
porphyrins. With the conventional separation of terms, small symmetry-breaking
distortions may lead to a complete reinterpretation of the MCD spectrum, although
there is no significant alteration in the electronic structure. In the polarization propagator approach the temperature-independent part of the MCD spectrum can be
treated in a unified manner, retaining the physical information of the excited states,
and it is thus a convenient tool for analyzing the spectrum.
P48
Molecular Properties ’09 - Posters
Reaction mechanism of Stearoyl-ACP Δ 9-Desaturase (Δ 9D):
Combined Computational and Spectroscopic Study
M. Srneca), J. K. Schwarz b), Y. Kwak b), L. Rulíšek a), E. I. Solomon b)
a) Institute of Organic Chemistry and Biochemistry AS CR, v.v.i, Flemingovo nám. 2,
Prague 6, Czech Republic
b) Department of Chemistry, Stanford University, Stanford, California 94305, U.S.A.
The soluble Δ 9-desaturase is a NADPH- and dioxygen-dependent enzyme with
binuclear non-heme iron active site catalyzing the insertion of the cis double bond
between the C9 and C10 position in stearoyl-ACP. Several spectroscopic studies
revealed essential geometrical and electronic changes accompanying the binding of the
substrate in the active site during catalytic cycle [1,2,3]. However, the reaction
mechanism remains unknown. Combining the spectroscopic (CD/MCD) and the
QM/MM methods, we have shown that substrate binding triggers changes in the
electronic structure of the active site which result in the formation of a stable 1,2-µperoxo-Δ9D complex. However, this intermediate complex does not correspond to the
fully activated active site attacking the substrate. Hence, the QM/MM techniques have
been considered as an excellent tool to analyze various oxidation and protonation states
of the pre-activated 1,2-µ-peroxo-Δ9D complex and provided a sound theoretical basis
for discussing the role of the ferredoxin as an enzymatic cofactor. In summary, the
complete reaction mechanism is proposed.
[1] Y.-S. Yang et al., J. Am. Chem. Soc., 121, 2770 (1999).
[2] E. I. Solomon., Inorg. Chem., 40, 3656 (2001).
[3] A. J. Skulan et al., J. Am. Chem. Soc., 126, 8842 (2004).
P49
Molecular Properties ’09 - Posters
Linear response QM/MM/PCM: Theory and applications
A. H. Steindala) , J. Kongstedb) , K. Ruuda) and L. Frediania)
a) Centre for Theoretical and Computational Chemistry, Department of Chemistry,
University of Tromsø, NO-9037 Tromsø, Norway
b) Department of Physics and Chemistry, University of Southern Denmark, DK-5230
Odense M, Denmark
We will present an implementation of a multiscaling approach for the investigation
of solvent effects on different molecular properties. In our approach, the solute will be
treated with QM. The short range effects of the solvent will be described by molecular
mechanics (MM), including a layer of solvent molecules as MM units. The long range
contributions will be described by a polarizable continuum model (PCM), by enclosing
the whole QM/MM system in a PCM cavity shaped by the system. The coupling between MM and PCM has been implemented up to linear response in a local version of
the Dalton program. To the best of our knowledge, this is the first implementation of a
linear response QM/MM/PCM scheme including polarizable MM units. Alongside the
theoretical aspects of the model, we will present results concerning the UV-VIS absorption spectra and NMR parameters of some model systems. In this preliminary results,
water has been used as solvent but the method can in principle be applied to any solvent
given an appropriate parametrization of the MM units. We also compare results from our
QM/MM/PCM approach with QM/MM, QM/PCM and QM calculations.
P50
Molecular Properties ’09 - Posters
Benchmarking density-functional-theory calculations of
rotational g tensors and magnetizabilities using accurate
coupled-cluster calculations
Andrew M. Tealea , Ola B. Lutnæsa , Trygve Helgakera , David J. Tozerb , Kenneth Ruudc ,
Jürgen Gaussd
a
Centre for Theoretical and Computational Chemistry, Department of Chemistry, University
of Oslo, P.O.B. 1033 Blindern, N-0315 Oslo, Norway
b
c
Department of Chemistry, Durham University, South Road, Durham, DH1 3LE,UK
Centre for Theoretical and Computational Chemistry, Department of Chemistry, University
of Tromsø, N-9037 Tromsø, Norway,
d
Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
We present [1] an accurate benchmark set of rotational g tensors and magnetizabilities calculated using coupled-cluster singles-doubles (CCSD) theory and coupled-cluster single-doublesperturbative-triples (CCSD(T)) theory, determined using (rotational) London atomic orbitals
[2–4]. The accuracy of the results obtained is established for the rotational g tensors by careful
comparison with experimental data, taking into account zero-point vibrational corrections [5].
Extrapolation techniques are used to provide estimates of the basis-set-limit quantities, thereby
establishing an accurate benchmark data set. The utility of the data set is demonstrated by
examining a wide variety of density functionals for the calculation of these properties, including their optimized-effective potential evaluations [6]. None of the density-functional methods
are competitive with the CCSD or CCSD(T) methods. The need for a careful consideration
of vibrational effects is clearly illustrated. Finally, the pure coupled-cluster results are compared with the results of density-functional calculations constrained to give the same electronic
density. The results quantify the importance of current dependence in exchange–correlation
functionals, commonly neglected in present-day calculations.
Figure 1: Mean relative errors (MREs, %) in the
calculation of rotational g-tensors compared with
the benchmark data set for the various wave function and DFT methods employed. The DFT results are grouped by functional type. The heights
of the bars correspond to the largest MRE in each
category.
[1] O. B. Lutnæs, A. M. Teale, T. Helgaker, D. J. Tozer, K. Ruud and J. Gauss, submitted, J. Chem. Phys.
[2] K. Ruud, T. Helgaker, K. L. Bak, P. Jørgensen and H. J. A. Jensen, J. Chem. Phys. 99, 3847 (1993)
[3] J. Gauss, K. Ruud and T. Helgaker, J. Chem. Phys. 105, 2804 (1996)
[4] J. Gauss, K. Ruud and M. Kállay, J. Chem. Phys. 127, 074101 (2007)
[5] K. Ruud, P.-O. Åstrand and P. R. Taylor, J. Chem. Phys. 112, 2668 (2000)
[6] W. Yang and Q. Wu, Phys. Rev. Lett. 89, 143002 (2002).
P51
Molecular Properties ’09 - Posters
Theoretical investigation of the electronic spectrum of pyrazine
Gabor J. Halász,1 Ágnes Vibók,2 Attila Papp,2 and Clemens Woywod3
1
Department of Information Technology, University of Debrecen, H-4010 Debrecen, PO Box 12, Hungary
2
Department of Theoretical Physics, University of Debrecen, H-4010 Debrecen, PO Box
3
Theoretical Chemistry (CTCC), Chemistry Department, University of Tromsø, N-9037 Tromsø
The electronic spectrum of pyrazine is studied by employing the complete active space self-consistent field
(CASSCF) and multiconfigurational second-order perturbation theory (CASPT2) methods. Oscillator strengths
have been calculated for various electronic transitions. Basis sets and active spaces were selected to provide
highly accurate results for vertical excitation energies and oscillator strengths. The computational task is significantly complicated by the simultaneous presence of valence and Rydberg excited states in the same energy
region, a constellation that can potentially lead to artificial valence-Rydberg mixing in the electronic wavefunctions. A related problem is the difficulty to include Rydberg-type basis functions into the active space. We have
developed a systematic approach for a consistent description of both valence and Rydberg excited states that
is verified by comparison with spectroscopic results. While many of the assignments made in previous studies
could be confirmed, there are also several new aspects emerging from the present investigation.
P52
Molecular Properties ’09 - Posters
An efficient approach for calculating rotation-vibration and temperature
corrections to molecular properties
A. Yachmenev, W. Thiel, Max-Planck-Institut für Kohlenforschung,
Kaiser-Wilhelm-Platz 1, D–45470 Mülheim an der Ruhr, Germany;
S. N. Yurchenko, Institut für Physikalische Chemie, TU Dresden,
D-01062 Dresden, Germany; P. Jensen, FB C – Theoretische Chemie,
Bergische Universität, D–42097 Wuppertal, Germany.
We present an efficient approach to compute various thermally averaged molecular properties of small molecules. Our approach is based on the direct evaluation of the matrix
exponent for a rotation-vibration Hamiltonian using the Taylor series expansion technique.
We utilize the FBR representation of the rotation-vibration Hamiltonian as implemented
in the in the computer program TROVE a . As an illustration we present results of thermal
averaging of a different molecular properties for H2 S and NH3 , such as of polarizability,
spin-spin coupling constants, chemical shifts, and equilibrium geometries. For these averaging we use high level ab initio calculations to evaluate the vibrational dependence of
the molecular property in question.
a
S. N. Yurchenko, W. Thiel, and P. Jensen, J. Mol. Spectrosc., 245, 126 (2007).
P53
Molecular Properties ’09 - Posters
Combining screened hybrid density functionals
with empirical dispersion corrections for extended
systems
Kazim E. Yousaf☆ and Edward N. Brothers
Texas A&M University at Qatar, PO Box 23874, Doha, Qatar
April 30, 2009
Abstract
The screened hybrid Heyd–Scuseria–Ernzerhof (HSE06) density functional [Heyd et al.,
J. Chem. Phys. 118, 8207 (2003); ibid. 124, 219906 (2006)] has been shown to significantly reduce the errors in calculated band gaps, lattice constants and bulk moduli of a
variety of solids compared to pure DFT. Issues related to the decay of Hartree–Fock exchange — long known to be important for accurate DFT calculations on molecules —
are avoided in the PBE-based HSE functional by splitting the exchange into long- and
short-range components. Only with this splitting, or screening, is the calculation of exact
exchange under periodic boundary conditions (PBC) tractable.
Regardless of the importance of exact exchange, however, it cannot improve the description of a system in which dispersion interactions are important. The DFT-D approach,
popularized by Grimme [S. Grimme, J. Comput. Chem. 25, 1463 (2004)], is a straightforward empirical prescription for calculating a dispersion correction to the energy (and its
derivatives) of a molecule or complex. Parametrized for a number of functionals, DFT-D
methods yield good geometries and especially accurate heats of formation for dispersionbound complexes, for example. For an N-atom system, the correction takes the simple
pairwise form
N−1 N Ci j
1
Edisp = −s6 ∑ ∑ 66
.
Ri j
− 1)]
i=1 j=i+1 Ri j 1 + exp[−d (
Rr
Our group has implemented the DFT-D formalism for energies and gradients under PBC
with Gaussian basis sets and determined the optimum scaling factor, s6 , for the HSE06
functional, thus allowing us to simultaneously include computationally tractable exact
exchange and accurate dispersion interactions in calculations on extended systems. We
will present the outline of our method, as well as the results of structure and property
calculations on a number of different systems.
P54
Participants
Participants at Molecular Properties '09
Francesco Aquilante
Department of Physical Chemistry,
University of Geneva
Switzerland
[email protected]
Victor Bernstein
Technion - Israel Institute of
Technology
Israel
[email protected]
Daniel Crawford
Virginia Tech
USA
[email protected]
Alexey Arbuznikov
University of Wuerzburg, Institute of
Inorganic Chemistry
Germany
[email protected]
Nick Besley
University of Nottingham
UK
[email protected]
Janusz Cukras
University of Warsaw
Poland
[email protected]
Michiko Atsumi
the CTCC, Department of Chemistry,
Univeristy of Oslo
Norway
[email protected]
Barbara Betancourt
Instituo de Investigaciones en
Materiales, UNAM
Mexico
[email protected]
Michael Deleuze
Hasselt University
Belgium
[email protected]
Gustavo Aucar
Institute of Modelling and Innovative
Technology, Northeastern University of
Argentina
Argentina
[email protected]
Stefano Borini
ETH Zurich
Switzerland
[email protected]
Wolfgang Domcke
Technische Universität München,
Department of Chemistry
Germany
[email protected]
Vebjørn Bakken
UiO
Norway
[email protected]
Raffaele Borrelli
Università di Salerno, Dipartimento di
Chimica
Italia
[email protected]
Ephraim Eliav
School of Chemistry, Tel Aviv
University
Israel
[email protected]
Radovan Bast
CTCC, University of Tromsø
Norway
[email protected]
Adam Chamberlin
University of Tromsø
Norway
[email protected]
Daniel Escudero Masa
Friedrich-Schiller Universität Jena
Germany
[email protected]
Leonardo Belpassi
Chemistry Department, University of
Perugia
Italy
[email protected]
Lan Cheng
College of Chemistry and Molecular
Engineering, Peking University
China
[email protected]
Stefano Evangelisti
Laboratoire de Chimie et Physique
Quantiques, University of Toulouse
France
[email protected]
Caterina Benzi
Università di Torino, Dipartimento di
Chimica
Italy
[email protected]
Sonia Coriani
CTCC, Kjemisk Institutt, Oslo,
Università degli Studi di Trieste
Italy
[email protected]
Nicolas Ferré
Université de Provence, Laboratoire
Chimie Provence
France
[email protected]
Participants at Molecular Properties '09
Filipp Furche
University of California, Irvine
USA
[email protected]
Michael Harding
Dept. of Chemistry and Biochemistry,
The University of Texas
USA
[email protected]
Stefan Janecek
Johannes Kepler University Linz,
Institute of Theoretical Physics
Austria
[email protected]
Bin Gao
University of Tromsø
Norway
[email protected]
Trygve Helgaker
Department of Chemistry, University of
Oslo
Norway
[email protected]
Branislav Jansik
Theoretical Chemistry, Aarhus
University
Denmark
[email protected]
Jurgen Gauss
Institut fur Physikalische Chemie,
Universitat Mainz
Germany
[email protected]
Sebastian Höfener
University of Karlsruhe
Germany
[email protected]
Sara Janssens
Free University of Brussels VUB
Belgium
[email protected]
Núria González-García
Universitaet Karlsruhe, Institut of
Physical Chemistry
Germany
[email protected]
Mark Hoffmann
University of North Dakota
USA
[email protected]
Michal Jaszunski
Institute of Organic Chemistry, Polish
Academy of Sciences
Poland
[email protected]
Luca Grisanti
Parma University, Dipartimento di
Chimica GIAF
Italy
[email protected]
Ida-Marie Høyvik
NTNU
Norway
[email protected]
Bogumil Jeziorski
Department of Chemistry, University of
Warsaw
Poland
[email protected]
Rui Guo
Department of Chemistry, Imperial
College London
UK
[email protected]
Maria Francesca Iozzi
CTCC, University of Oslo
Norway
[email protected]
Dan Jonsson
CTCC, Tromsø
Norway
[email protected]
Johannes Hachmann
Cornell University, Department of
Chemistry and Chemical Biology
USA
[email protected]
Suehiro Iwata
Toyota Physical and Chemical
Research Institute
Japan
[email protected]
Poul Jørgensen
Department of Chemistry, Aarhus
University
Denmark
[email protected]
Balazs Hajgato
Vrije Universiteit Brussel, Hasselt
University
Belgium
[email protected]
Christoph Jacob
ETH Zurich, Laboratorium für
physikalische Chemie
Switzerland
[email protected]
Jonas Juselius
University of Tromsø, CTCC
Norway
[email protected]
Participants at Molecular Properties '09
Muneaki Kamiya
Gifu University
Japan
[email protected]
Michal Kolar
Institute of Organic Chemistry and
Biochemistry, Academy of Sciences of
the Czech Republic
Czech Republic
[email protected]
Wenjian Liu
College of Chemistry and Molecular
Engineering, Peking University
China
[email protected]
Joanna Kauczor
University of Aarhus
Denmark
[email protected]
Jacek Komasa
A.Mickiewicz University, Faculty of
Chemistry
Poland
[email protected]
Hans Peter Lüthi
ETH Zrich, Deparment of Chemistry
and Applied Biosciences
Sveits
[email protected]
Anne-Marie Kelterer
Graz University of Technology, Institute
of Physical and Theoretical Chemistry
Austria
[email protected]
Tatiana Korona
University of Warsaw, Faculty of
Chemistry
Poland
[email protected]
Alejandro Maldonado
Institute of Modelling and Innovative
Technology, Northeastern University of
Argentina
Argentina
[email protected]
Bernard Kirtman
University of California, Santa Barbara
USA
[email protected]
Andreas Krapp
Universitet i Oslo
Norway
[email protected]
Shuneng Mao
College of Chemistry and Molecular
Engineering,, Peking University,
Beijing, China
China
[email protected]
Thomas Kjaergaard
Aarhus University
Denmark
[email protected]
Kasper Kristensen
Aarhus University
Danmark
[email protected]
Christel Marian
Heinrich Heine University, Theoretical
and Computational Chemistry
Germany
[email protected]
Wim Klopper
University of Karlsruhe
Germany
[email protected]
Tomas Kubar
Technische Universität Braunschweig
Germany
[email protected]
Guglielmo Monaco
Dipartimento di Chimica, Università di
Salerno
Italy
[email protected]
Peter Knowles
Cardiff University
UK
[email protected]
Henry Kurtz
University of Memphis
USA
[email protected]
Antonio Monari
Dip. Chimica Fisica ed Inorganica,
Università di Bologna
Italy
[email protected]
Rika Kobayashi
Australian National University
Australia
[email protected]
Dimitrios Liakos
Institute for Physical and Theoretical
Chemistry, Wegelerstrasse 12, 53115
Bonn, Germany.
Germany
[email protected]
Hirotoshi Mori
Ochanomizu University, Ocha-dai
Academic Production
Japan
[email protected]
Participants at Molecular Properties '09
Harald Møllendal
University of Oslo
Norway
[email protected]
Massimo Olivucci
University of Siena and, Bowling Green
State University
Italy
[email protected]
Cristina Puzzarini
Dipartimento di Chimica, University of
Bologna
Italy
[email protected]
Debashis Mukherjee
Indian Association for the Cultivation of
Science, Kolkata 700032
India
[email protected]
Krzysztof Pachucki
Institute of Theoretical Physics,
University of Warsaw
Poland
[email protected]
Guntram Rauhut
Universitaet Stuttgart, Institut fuer
Theoretische Chemie
Germany
[email protected]
Hiromi Nakai
Waseda University
Japan
[email protected]
Shubhrodeep Pathak
Indian Association for the Cultivation of
Science
India
[email protected]
Inga Respondek
Theory group SFB 569, Ulm University
Germany
[email protected]
Eric Neuscamman
Cornell University, Department of
Chemistry and Chemical Biology
USA
[email protected]
Magdalena Pecul-Kudelska
Faculty of Chemistry, University of
Warsaw, Center for Computational and
Theoretical Chemistry
Poland
[email protected]
Daniel Rohr
Technical University Lodz, Institute for
Physics
Poland
[email protected]
Marcel Nooijen
Chemistry department, University of
Waterloo, Ontario
Canada
[email protected]
Thomas Bondo Pedersen
Centre for Theoretical and
Computational Chemistry, University of
Oslo
Norway
[email protected]
Piotr Rozyczko
Accelrys, Inc
UK
[email protected]
Christian Ochsenfeld
Theoretical Chemistry, Universitaet
Tuebingen
Germany
[email protected]
Andrea Peluso
Dipartimento di Chimica, Universita' di
Salerno
Italy
[email protected]
Lubomír Rulíšek
Institute of Organic Chemistry and
Biochemistry, Academy of Sciences of
the Czech Republic
Czech Republic
[email protected]
Koichi Ohno
Toyota Physical and Chemical
Research Institute
Japan
[email protected]
Teemu O. Pennanen
University of Helsinki, Dep. of
Chemistry, Lab. of Phys. Chem.
Finland
[email protected]
Kenneth Ruud
CTCC, Department of Chemistry,
University of Tromsø
Norway
[email protected]
Malgorzata Olejniczak
Faculty of Chemistry, University of
Warsaw
Poland
[email protected]
Michal Przybytek
Department of Chemistry, University of
Oslo
Norway
[email protected]
Vladimir Rybkin
University of Oslo, CTCC
Norway
[email protected]
Participants at Molecular Properties '09
Espen Sagvolden
Department of Chemistry, University of
California, Irvine
USA
[email protected]
Erik Tellgren
CTCC, Department of Chemistry,
University of Oslo
Norway
[email protected]
Clemens Woywod
University of Tromsø, CTCC
Norway
[email protected]
Hiroko Satoh
National Institute of Informatics
Japan
[email protected]
David Tozer
Durham University
UK
[email protected]
Andrey Yachmenev
Max-Planck-Institut fuer
Kohlenforschung
Germany
[email protected]
Didier Siri
Université de Provence
France
[email protected]
Edward Valeev
Virginia Tech
USA
[email protected]
Kizashi Yamaguchi
Osaka University, Graduate School of
Science, Dept. of Chemistry
Japan
[email protected]
Harald Solheim
University of Tromsø, CTCC
Norway
[email protected]
Troy Van Voorhis
MIT
USA
[email protected]
Takeshi Yanai
Institute for Molecular Science
Japan
[email protected]
Martin Srnec
IOCB AVCR
Czech Republic
[email protected]
Lucas Visscher
VU University, Section Theoretical
Chemistry
Netherlands
[email protected]
Kazim Yousaf
Texas A & M University at Qatar
Quatar
[email protected]
Arnfinn Hykkerud Steindal
CTCC, University of Tromsø
Norway
[email protected]
Ville Weijo
CTCC, Universitetet i Tromsø
Norway
[email protected]
Ying Zhang
Xiamen University
China
[email protected]
Krzysztof Szalewicz
U. Delaware
USA
[email protected]
Hans-Joachim Werner
Institute for Theoratical Chemistry,
University of Stuttgart
Germany
[email protected]
Andrew Teale
University of Oslo
Norway
[email protected]
Richard Wheatley
School of Chemistry, University of
Nottingham
UK
[email protected]