Abstracts of Invitedand Contributed Talks, Sep. 7201

7A1-1IInterfacial dipole and geminate pair energetics
at pentacene/C60 heterojunctions
Frédéric Castet1, Laurent Ducasse1, Julien Idé1, Stijn Verlaak2, Alexander Mityashin2,
Cédric Rolin2, Paul Heremans2, Mathieu Linares3, Jérôme Cornil3, David Beljonne3
1

Université de Bordeaux, Institut des Sciences Moléculaires, UMR 5255 CNRS,
351 Cours de la Libération, 33405 Talence, France 2 imec, Kapeldreef 75, B-3001
Leuven, Belgium Katholieke Universiteit Leuven, Arenbergpark, B3001 Leuven,
Belgium 3 Laboratory for Chemistry of Novel Materials, University of Mons UMONS,
Place du Parc 20, B-7000 Mons, Belgium
Among the successive steps describing the light-to-electricity conversion process inorganic photovoltaic cells, the splitting of the Coulomb bound electron-hole pairs at thedonor/acceptor interface into free charge carriers remains an open question. The
so-called electric-field assisted mechanism assumes that interfacial electric fields,
arising from local interfacial dipoles, can favor the charge separation [1].
To characterize the dipole moments at pentacene/C60 heterojunctions, we havecoupled quantum-chemical and microelectrostatic (ME) calculations on molecularaggregates of various sizes and shapes. The results show that the interfacial dipoles
mostly originate in polarization effects due to the asymmetry in the multipolar
expansion of the electronic density distribution between the interacting molecules. The
local dipoles are found to fluctuate in sign and magnitude over the interface and appear
as sensitive probes of the relative arrangements of the pentacene and C60 molecules [2].
Then, the geminate pair energetics at the pentacene/C60 interface has beenaddressed by increasing the electron-hole separation across the interface. The results
indicate that geminate pair dissociation critically depends on the orientation of thepentacene π-system relative to the adjacent C60. Indeed, these calculations predict thatrecombination of the electron-hole pairs is favored over separation at the
pentacene(011)/C60 interface, while the geminate pair splitting can easily occur at the
pentacene(01-1)/C60 interface [3].

[1] V. I. Arkhipov, P. Heremans, H. Bässler, Appl. Phys. Lett. 2003, 82, 4605.
[2] M. Linares, D. Beljonne, J. Cornil, K. Lancaster, J.L. Brédas, S. Verlaak, A.
Mityashin, P. Heremans, A. Fuchs, C. Lennartz, J. Idé, R. Méreau, P. Aurel, L. Ducasse,
F. Castet J. Phys. Chem. C, 2010, 114, 3215.
[3] S. Verlaak, D. Beljonne, D. Cheyns, C. Rolin, M. Linares, F. Castet, J. Cornil, and P.
Heremans Adv. Funct. Mat. 2009, 19, 3809.

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203

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7A1-5I
Theories and applications for electronic coupling in electronic transfer andexcitation energy transfer
Chao-Ping Hsu
128 Section 2, Academia Road, Institute of Chemistry, Academia Sinica
Nankang, Taipei, 115, Taiwan

The transport of charges and excitation energy are two processes of fundamental
importance in diverse areas of research. Characterizations of electron transfer (ET) andexcitation energy transfer rates are essential for a full understanding of many biologicalsystems and opto-electronic devices. The electronic coupling factor is an off-diagonal
Hamiltonian matrix element between the initial and final diabatic states in the transport
processes. ET coupling is essentially the interaction of the two molecular orbitals (MOs)where the electron occupancy is changed. Singlet energy transfer (SET) contains a
Förster dipole–dipole coupling term as its most important constituent. Triplet energy
transfer (TET) involves an exchange of two electrons of different spin and energy; thus, it
is like an overlap interaction of two pairs of MOs.
In the past, we have developed or improved the strategies for calculating ET, SET, andTET couplings. In the presentation, I plan to report (1) the theory and development in thecharacterization of SET coupling with application examples. The fragment excitationdifference (FED) is developed to calculate SET coupling, which yields the overall
coupling under the Hamiltonian employed, including the through-bond, exchange andorbital overlap effects. With FED and a precise account of the Coulomb coupling, theexchange and overlap effects on SET can be studied. And, (2) our recent progresses in
the charge transport properties in tris(8-hydroxyquinolinato)aluminum(III) (AlQ3). With
intermolecular configurations derived from crystal structures, we found that most of thecommonly seen configurations with π -π interaction are further stabilized with CH-πinteractions involving other ligands on AlQ3. The CH-π interaction drives the structure of
the AlQ3 pair towards a large lowest unoccupied molecular orbital (LUMO) overlap, anda small overlap in the highest occupied molecular orbital (HOMO), accounting for the
preference in electron transport.This result provides an insight for the charge transport
properties for AlQ3 from the structural perspectives, which is important for designing
new materials with desirable charge transfer property.

204

7A2-1I
Quantum Dots – Artificial Atoms, Large Molecules or Small Pieces of Bulk?
Insights from Time-Domain Ab Initio Studies.
Oleg Prezhdo
University of Rochester, USA
Quantum dots (QD) are quasi-zero dimensional structures with a unique combination ofsolid-state and atom-like properties. Unlike either bulk or atomic materials, QD properties
can be modified continuously by changing QD shape and size. Often, the bulk and atomic
viewpoints contradict each other, leading to differing predictions about the behavior of
QDs. For example, the atomic view suggests strong electron -hole and charge-phonon
interactions, as well as slow energy relaxation due to mismatch between electronic energy
gaps and phonon frequencies. In contrast, the bulk view advocates that the kinetic en ergyof quantum confinement is greater than electron-hole interactions, that charge-phonon
coupling is weak, and that the relaxation through quasi -continuous bands is rapid.
QDs exhibit new physical phenomena. In particular, the so-called phonon bottleneckto the electron and hole energy relaxation and generation of multiple excitons uponabsorption of a single photon can be used to improve efficiencies of photovoltaic devices.
Slowing down of the energy relaxation can result in extraction of hot electrons and holes,
thereby increasing the solar cell voltage. Generation of multiple electron-hole pairs canincrease the current.
Our state-of-the-art non-adiabatic molecular dynamics techniques, implemented
within time-dependent density functional theory, allow us to model the response of QDs at
the atomistic level and in real time.

The studies provide a unifying description ofquantum dynamics in nanoscale materials, resolve the debated issues, and generatetheoretical guidelines for development of novel systems for solar energy harvesting andother applications.
1. C. F. Craig, W. R. Duncan, O. V. Prezhdo, Phys. Rev. Lett., 95 163001 (2005).
2. O. V. Prezhdo, Acc. Chem. Res., 42, 2005 (2009).
3. A. B. Madrid, H.-D. Kim, O. V. Prezhdo, ACS-Nano, 3, 2487 (2009).
4. S. A. Fischer, C. M. Isborn, O. V. Prezhdo, Chem. Science, 2, 400 (2011).
5. Kim H.-D., O. V. Prezhdo, Nano Lett., 11, 1845 (2011).

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Electron Tunneling in Respiratory Complex I
Tomoyuki Hayashi,1 Alexei A. Stuchebrukhov,1
1
Department of Chemistry, University of California, Davis, California
I. Introduction
NADH:ubiquinone oxidoreductase (complex I) plays a central role in the
respiratory electron transport chain by coupling the transfer of electrons from NADH toubiquinone to the creation of the proton gradient across the membrane necessary for
ATP synthesis. The crystal structure of hydrophilic domain of complex I from Thermus
thermophilus was reported in 2006 [1]. However, until now, the atomistic details ofelectron transfer along the chain of Fe/S metal clusters have remained unknown. In thisstudy, the atomistic details of electron tunneling along seven Fe/S clusters in complex I
are examined by using the tunneling current theory and computer simulations [2].
II. Electron Tunneling Pathways
Distinct electron tunneling pathways between neighboring Fe/S clusters are
identified; the pathways primarily consist of two cysteine ligands and one additional
key residue. The identified key residues are further characterized by sensitivity ofelectron transfer rates to their mutations, examined in simulations, and theirconservation among complex I homologues.
III. Enhancement of Electron Transfer Rates due to the Internal Water
Internal water between protein subunits
is identified as an essential mediator
enhancing the overall electron transfer
rate by almost three orders of magnitude
to achieve a physiologically significant
value. With the water included, thenegative slope of the distancedependence of the electron transfer rates
becomes close to a typical 1.4 in natural
logarithm [3]. The unusual electronic
structure properties of Fe/S clusters incomplex I explain their remarkableefficiency of electron transfer.
[1] L. A. Sazanov, and P. Hinchliffe,
Science 311, 1430 (2006).
[2] T. Hayashi, and A. A. Stuchebrukhov,
Proc. Natl. Acad. Sci. U. S. A. 107,
19157 (2010).
[3] C. C. Moser, C. C. Page, and P. L.
Dutton, Philos. Trans. R. Soc. B 361,
1295 (2006).

Figure 1. Calculated complete electron
tunneling pathways from FMN to N2 ofcomplex I. The atoms with significant
electrontunneling
probability
arehighlighted with red color intensity
corresponding to their total atomic currents.

206

7A3-1C

Theoretical Study of the Structure Order in Supercritical Water
Haibo Ma,1 Jing Ma,1
1
Institute of Theoretical and Computational Chemistry, Key Laboratory of
Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering
Nanjing University, Nanjing, 210093, China
In the recent years, supercritical water (SCW) has attracted intensive researchinterests because of its important potential as an environmentally benign green alternative to toxic organic solvents. Most of precious theoretical investigations about
SCW were devoted to the the hydrogen bonding network and its inﬂuence on physicochemical properties as well as local density inhomogeneities in SCW.[1-3] It was
revealed that hydrogen bonds still exist in SCW but their number will decrease
with the increase of temperature or the decrease of the density. The decrease ofhydrogen bonds induces the local density inhomogeneities, which is the microscopic
origin of the enhanced solubility of SCW. However, the structure order of SCW havereceived relatively little attention. Actually, the anomalous kinetic and thermodynamic properties of water have long been been found to be able to be interpreted
qualitatively in terms of underlying structural causes.[4]In this work, we present studies on the structure order of SCW along a supercritical isotherms, T = 1.03 Tc (Tc = 666 K), and over a wide density range, from 0.01
to 2.0 ρc (ρc =0.322 g/cm3 ), by isochoric-isothermal molecular dynamics simulationsof the simple point charge extended (SPC/E) model. It is found that the translational structure order is nearly invariant under supercritical conditions regardless of
their diﬀerent bulk densities and it is signiﬁcantly lower than that of the ambient
water. Meanwhile, the enhanced energy ﬂuctuation under supercritical conditions
make some energetically unfavorable water-dimer structures emerge. Therefore, thepure rOH -based geometric criterion which is widely used in the hydrogen bonding(HB) statistics under normal liquid water conditions is not applicable for SCW. The
further inclusion of a energy-based criterion or a more general geometrical criterion
is needed in the HB statistics under supercritical conditions. At the same time, theorientational tetrahedral order parameter decreases from positive to negative withthe decreasing SCW bulk density due to the emergence of energetically unfavorable
water-dimer structures by the enhanced ﬂuctuations. When the SCW tends to be
gas-like with very small bulk density, the orientational tetrahedral order parameter increases and approaches to zero because of the signiﬁcant disorder and strong
ﬂuctuation.
[1] S. C. Tucker, Chem. Rev. 99, 391 (1999).
[2] I. Skarmoutsos and J. Samios, J. Phys. Chem. B 110, 21931 (2006).
[3] I. Skarmoutsos, D. Dellis and J. Samios, J. Phys. Chem. B 113, 2783 (2009).
[4] J. R. Errington and P. G. Debenedetti, Nature 409, 318 (2001).

207

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Spanning QTAIM Topology Phase Diagrams of Isomer Sets.
Samantha Jenkins1, Albeiro Restrepo2, Jorge David3, Steven Robert Kirk1 , Chunying
Rong1, Shubin Liu4, and Dulin Yin1.
1
College of Chemistry and Chemical Engineering, Hunan Normal University,
Changsha, Hunan 410081, China.
2
Instituto de Química, Universidad de Antioquia, AA 1226 Medellín, Colombia.
3
Departamento de Ciencias Basicas, Universidad Eafit, AA 3300, Medellin, Colombia.
4
Research Computing Center, University of North Carolina,
Chapel Hill, North Carolina 27599-3420.

Structural and chemical properties of a variety of isomer sets including the small
clusters of water W4, W5 and W6, (SiO2)6 [1, 2] and lithium respectively are investigatedwith the quantum theory of atoms and molecules (QTAIM). We then proceed to extend
the isomer sets topology space using QTAIM; the Poincaré-Hopf topological sum rules
are applied to create rules to identify the spanning set of conformer topologies. The
topological stability of degenerate solutions to the Poincaré-Hopf relation are comparedby evaluating the proximity to rupturing of critical points of the gradient vector field of
the charge density. We introduce a QTAIM topology space to replace the inconsistentuse of Euclidean geometry to determine whether a cluster is -1, -2 or 3-D. In particular,
we show from the topology of the charge density that the conformers of the W4, W5
clusters are more energetically stable in less compact, planar forms, in contrast, theconformers of W6 are more energetically stable with compact 3-D topologies.
Quantifying the degree of covalent character in the hydrogen bonding [3] for the W 4, W5
and W6 clusters independently verifies this finding. Conversely our new quantum
topological definition of geometry shows that the four most energetically stable (SiO2)6
conformers are quantified as two-dimensional (2-DQT) within the new quantum
topology.

[1] 'Spanning QTAIM Topology Phase Diagrams of Water Isomers W4, W5 and W6.', S.
Jenkins, Al. Restrepo, J. David, D. Yin and S. R. Kirk, accepted to appear in Phys.
Chem. Chem. Phys.
[2] 'Spanning Set of Silica Cluster Isomer Topologies from QTAIM', S. Jenkins, C.
Rong, S.R. Kirk, D. Yin, and S. Liu, accepted to appear in J. Phys. Chem A.
[3] 'The Chemical Character of the Intermolecular bonds of Seven Phases of Ice as
Revealed by Ab-initio Calculation of Electron Densities', S. Jenkins and I. Morrison,
Chem. Phys. Lett., 317(1-2)), 97-102, (2000).

208

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Water Catalyzed Overtone Induced Reaction for Hydrate
Fluoromethanol: Fact of Fiction?
Kaito Takahashi1 Zeb C. Kramer2, and Rex T. Skodje2
1
Institute of Atomic and Molecular Sciences, Academia Sinica Taipei, Taiwan
2
Department of Chemistry and Biochemistry, University of Colorado Boulder
I. Introduction
For Diels-Alder, dehalogation, dehydration and decarboxylation reactions,reactivity in the aqueous phase is much greater than in the gas phase. Using the hydrate
cluster model, previous quantum chemistry studies have provided answers to this byshowing that the existence of water can lower the potential energy barrier of severalhydrogen transfer reactions [1]. For thermal reactions this analysis based on thepotential barrier height is appropriate to provide explanations to the aforementioned trend.
On the other hand, one is not certain if this analysis stays valid for situations that startwith a “non-equilibrium state” such as initiation of reaction by a photon using overtone
excitation, spontaneous internal conversion, or stimulated emission. In the present study
we performed “on the fly” dynamics simulations using B3LYP/6-31+G(d,p) to quantify
the plausibility of water catalyzed overtone induced reaction using the HF elimination of+hQ
fluoromethanol
hydrateclustersasexample,CH2FOH…(H2O)n→CH2O+HF+(H2O)n n=1,2,3.[2]II. Results and Discussion
As can be seen in Figure 1,
the addition of water causes thebarrier height of the HF
elimination reaction to decrease
from 40 (green arrow) to 20 (bluearrow) and 15 kcal/mol (redarrow) for the mono and dihydrate,
respectively. On the other hand,when one looks at the quantum
yield of the dynamics simulation Figure 1. Quantum Yield of reactive trajectories
results (circles and squares) one versus photon energy for mono- (blue) and dican clearly see that the reaction (red) hydrate fluoromethanol clusters. Barrier
turns on at a much larger energy, height positions are also given with arrows
55 and 38 kcal/mol for mono anddehydrate, respectively. Thereby showing that the non-equilibrium distribution of theovertone excitation causes a delay in the threshold energy and water does not catalyze theovertone induced reaction in the present case.
[1] K Morokuma et al., J. Am. Chem. Soc.116, 10316 (1994). D. J. Donaldson etl al. J
Chem Phys A, 109, 9653, (2005). J. S. Fransisco et al. J Phys Chem A 113, 5333 (2009).
[2]R. T. Skodje et al. J. Am. Chem. Soc. 132, 15154 (2010).

209

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Low energy structures of (H2O)25 studied with Basin Paving Monte Carlosimulation and with perturbation theory based on locally projected molecular orbitals
Sudhanshu Shanker1, Pradipta Bandyopadhyay1 and Suehiro Iwata2
1
School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi,
India,
2
Toyota Physical and Chemical Research Institute, Nagakute, Aichi-gun, Aichi, 480-1192 Japan
Finding low energy structures of water clusters and estimation of their relative energies is one of
the most challenging problems in physical chemistry. Although there is a large body of works forsmaller water clusters, for clusters of size more than 20, the number of works is limited. The difficulty in investigating large water clusters comes from two reasons. First is the large number oflow energy distinct structures, which grows rapidly with the system size. The second is the difficulty in accurate estimation of the relative energies among the different isomers of the cluster. In
this work, we have investigated water cluster of size 25 by performing (a) Basin Paving Monte
Carlo simulation [1] using the effective fragment potential (EFP) [2] and (b) the third order single excitation perturbation theory based on the locally projected molecular orbitals (LPMO
3SPT), which is an efficient ab initio MO
method approximating the counterpoisecorrected SCF binding energy.[3] Figure

Comparison of the relative energies evaluated by
EFP1 and the LP MO 3rd SPT

demonstrates the very good correlation of
the binding energies among the isomers of(H2O)25. The isomers are found by theBasin Paving Monte Carlo simulation,
which is a non-Boltzmann sampling bychanging the probability of finding structures dynamically based on the history of
the simulation.
Reference:[1] P. Bandyopadhyay, Chem. Phys. Lett.,
487, 133 (2010). [2] M. S. Gordon, M. A. Freitag, P. Bandyopadhyay, J. H. Jensen, V. Kairys,
W. J. Stevens, J.Phys,Chem. A 105, 293 (2001) [3] S. Iwata , J. Phys. Chem. A, 114, 8697 (2010)210

7A3-5C

Structure and chemical activity of transition metal oxides and new
carbon K4 structures: A Theoretical DFT Study
Nurbosyn U. Zhanpeisov
Institute for International Education & Department of Chemistry,
Graduate School of Science, Tohoku University, Japan
Transition metal oxides are particularly interesting systems because of their welldefined framework structures, the wealth of experimental studies, and theirtechnological and industrial importance as catalysts, adsorbents, supports, etc. Recently,
a remarkable mathematical basis is given for the new allotropic structure of carbon(denoted as K4 crystal) because of its high symmetry and similar decagonal rings withthe three-coordinated and three-dimensional crystal structure. However, there are no
systematic cluster calculations to shed light on tiny properties of these compounds andfor a number of fundamental reactions that take place on their surface.
We present here the recent our results of DFT cluster quantum chemical calculations
on structures and chemical activity of representative transition metal oxides and newmetallic carbon K4 crystal having high surface areas. First, we underline the ultimate
importance of proper modeling the structure and chemical activity of transition metaloxides as well as support structures to understand the mechanism of formation of
precursor defect structures on TiO2(110) and other surface catalytic reactions. Next wewill demonstrate that the use of the finite cluster approach has well defined advantages in
shedding light on tiny properties of these materials and could be complimentary for otherband structure or periodic slab calculations. Based on the results obtained, somediscrepancies with the results of other theoretical studies in literature will be criticallypointed out.

211

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Interface Water on TiO2 Anatase (101) and (001) Surfaces:
First-Principles Study with TiO2 Slabs Dipped in Bulk Water
Masato Sumita,1 Chunping Hu,2 Yoshitaka Tateyama1,3
1
WPI International Centre for Materials Nanoarchitectonics (MANA), National Institutefor Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan2
Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo
162-8601, Japan
3
PRESTO and CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho,
Kawaguchi, Saitama 333-0012, Japan
We investigated the TiO2 anatase (101) and (001) interfaces dipped in bulk water on theatomic scale by first-principles density-functional molecular dynamics (MD)simulations. We verified that the water adsorption models proposed in the previous
studies with less than a couple of water layers on the vacuum surfaces still hold. On thecontrary, novel adsorption structures of interfacial water molecules are also found. Our
results indicate that water molecules around the interface between the TiO2 and bulk
water can be described by the following two-layer model: The first water layer can be
defined as the water molecules adsorbed at Ti5C sites moleculary on the anatase (101)surfaces and dissociatively on the (001). Second layer on the anatase (101) surface canbe defined as the water molecules adsorbed to O2C or adsorbed water to Ti5C via strong
HB. Second layer on the (001) consists of water molecules bound to the first-layer watermolecules via the strong and weak HBs. Contour maps of the atomic densities show thatwater molecules in the second layers are relatively mobile. This two-layer model wellaccounts for the experimental results ofsolid-state 1H-NMR. The presence of strong
HBs regardless of the water adsorption
manners suggests that OH termination does
not strongly affect the interfacial water
structure, and the surfaces of TiO2 anatasenanocrystals are hydrophilic intrinsically,leading to novel scenarios for the Fig. 1. A snapshot in the equilibrium trajectory offirst-principles molecular dynamics of TiO2 anatase (101)photocatalytic reaction mechanism.
surface dipped in bulk water.
[1] M. Sumita, C. Hu, and Y. Tateyama, J. Phys. Chem. C, 114 (2010), 18529.

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Real-time electron dynamics with correlated wavefunction methods
Peter Saalfrank,1 Tillmann Klamroth,1 Jean Christophe Tremblay,1 Stefan
Klinkusch,1 Pascal Krause,2 Mathias Nest3
1
Institute for Chemistry, University of Potsdam, Potsdam, Germany
2
Department of Chemistry, Temple University, Philadelphia, USA
3
Institute for Chemistry, Technical University Munich, Munich, Germany
In recent years, due to progress made in generating and controlling intense laserﬁelds, the timescale of dynamical processes in atomic and molecular systems has
been pushed into the attosecond domain (1 as=10−18 s). In parallel with experiments, theoretical methods are being developed to treat explicitly time-dependent
electronic motion after photoexcitation. This talk describes correlated, explicitly
time-dependent, wavefunction based N-electron methods as alternatives to real-time
density functional theory, and their application to selected molecular problems.
The focus of the talk is on many-electron methods in which the time-dependentN-electron wavefunction is expanded as a sum of Slater determinants. The ﬁrst approach of this type to be described is time-dependent conﬁguration interaction (TDCI), where only the coeﬃcients of the determinants are time-dependent. The second
approach is the time-dependent complete active space SCF method (TD-CASSCF),
for which both the coeﬃcients and Slater determinants are time-dependent. Extensions of the methods to include ionization, dissipation, and optimal control strategies
for excited electron dynamics, are also presented.
The methods will be applied (i) for laser-pulse excitation and switching of realmolecules without [1] and with [2] dissipation and / or ionization, (ii) for the calculation of response properties of small molecules [3], (iii) for long-range intermolecularcharge transfer [4], and (iv) for controlled electron dynamics in molecules [5].
[1] P. Krause, T. Klamroth, and P. Saalfrank, J. Chem. Phys. 123, 074105-1-7(2005); M. Nest, R. Padmanaban, and P. Saalfrank, J. Chem. Phys. 126 2141061-6 (2007); M. Nest, T. Klamroth, and P. Saalfrank, Zeitschr. Phys. Chem. 224,
569-581 (2010).
[2] J.C. Tremblay, T. Klamroth, and P. Saalfrank, J. Chem. Phys. 129, 084302-1-8(2008); S. Klinkusch, P. Saalfrank, and T. Klamroth, J. Chem. Phys. 131, 1143041-8 (2009); J.C. Tremblay, T. Klamroth, S. Klinkusch, and P. Saalfrank, J. Chem.
Phys. 134, 044311-1-10 (2011).
[3] P. Krause, T. Klamroth, and P. Saalfrank, J. Chem. Phys. 127, 034107-1-10(2007); J.C. Tremblay, P. Krause, T. Klamroth, and P. Saalfrank, Phys. Rev. A
81, 063420-1-10 (2010).
[4] S. Klinkusch, T. Klamroth, and P. Saalfrank, Phys. Chem. Chem. Phys. 11,
3875-3884 (2009).
[5] J.C. Tremblay and P. Saalfrank, Phys. Rev. A 78, 063408-1-9 (2008).

213

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Mössbauer spectroscopy for heavy elements:
a 4-component relativistic study
Stefan Knecht1 and Trond Saue2
1 University of Southern Denmark; Department of Physics and Chemistry

2 CNRS/Université de Toulouse 3 (Paul Sabatier); Laboratoire de Chimie et Physique Quantiques (UMR 5626)

Figure 1: Dominant contributions (in atomic units a−30 ) to projection analysis of relative contact densities of mercury
ﬂuorides at the 4-component relativistic HF and LDA level. pol=polarization, hyb=hybridization.

Mössbauer spectroscopy is an example of a spectroscopic technique showing extreme sensitivity to the electronic density in nuclear regions such that its modelling requires consideration of relativistic effects even for quite
light species. In the present talk we report 4-component relativistic studies of the contact density (the density at
the nucleus) of molecular species containing the Mössbauer active elements mercury[1] and xenon. We investigate the performance of relativistic density functional theory, using coupled-cluster calculations for calibration.
We present a detailed analysis of the observed relative contact densities between molecular species, bringing into
light the effect of polarization as well as overlap between ligands and the central atom. All calculations have been
carried out with the DIRAC code for relativistic molecular calculations [2].

References[1] Stefan Knecht, Samuel Fux, Robert van Meer, Lucas Visscher, Markus Reiher, and Trond Saue. Mössbauer spectroscopy for heavy
elements: a relativistic benchmark study of mercury. Theor. Chem. Acc., 2011. DOI: 10.1007/s00214-011-0911-2.
[2] DIRAC, a relativistic ab initio electronic structure program, Release DIRAC10 (2010), written by T. Saue, L. Visscher and
H. J. Aa. Jensen, with contributions from R. Bast, K. G. Dyall, U. Ekström, E. Eliav, T. Enevoldsen, T. Fleig, A. S. P. Gomes,
J. Henriksson, M. Iliaš, Ch. R. Jacob, S. Knecht, H. S. Nataraj, P. Norman, J. Olsen, M. Pernpointner, K. Ruud, B. Schimmelpfennig, J. Sikkema, A. Thorvaldsen, J. Thyssen, S. Villaume, and S. Yamamoto (see http://dirac.chem.vu.nl).

214

7B1-5C

Electronic excited states of large conjugated molecules
Ryoichi Fukuda,1,3 Masahiro Ehara,1,3 Hiroshi Nakatsuji2,31
Institute for Molecular Science and Research Center for Computational Science, Japan
2
Quantum Chemistry Research Institute, Japan
3
Japan Science and Technology Agency, CREST, Japan
Electronic structure and electronic excitations of large ʌ-conjugated molecules suchas porphyrins and phthalocyanines are being widely studied because of their importancein many fields. However, accurate calculations of electronic excited states of large
ʌ-conjugated systems are still challenging subjects because of their computational costs
and delocalized characters. Recently, we have developed the direct SAC-CI method [1]that can be applied to excited states of large systems within moderate computational costs
and reasonable accuracy. The method combined an efficient MO direct scheme andperturbation-selection technique that does not assume local nature of systems.
The electronic absorption spectra of free-base tetraazaporphyrins (H2TAP: C16H10N8),
phthalocyanines (H2Pc: C32H18N8), naphthalocyanines (H2Nc: C48H26N8), andanthracocyanines (H2Ac: C64H34N8) were calculated by the direct SAC-CI method.[2] As
shown in Fig. 1, the direct SAC-CI well reproduced the experimental spectra[3]. The
TDDFT calculations with common
functionals have some problems for these
extended systems. Electron correlation in
the excited states is very important toreproduce the experimental findings ofthese molecules.

Fig. 1 Experimental and theoretical spectra.
[1] R. Fukuda, H. Nakatsuji, J. Chem. Phys. 128, 094105 (2008).
[2] R. Fukuda, M. Ehara, H. Nakatsuji, J. Chem. Phys. 133, 144316 (2010).
[3] N. Kobayashi, S. Nakajima, H. Ogata, T. Fukdua, Chem, Eur, J, 20, 6294 (2004).

215

7B1-6C

Absorption and Emission properties of the F, OH and NO2 Substituted
Cinnamates: A TD-DFT Investigation
Malinee Promkatkaew,1,2 Songwut Suramitr,1,2 Thitinun Karpkird,1,3 Supa Hannongbua1,2*
1

Department of Chemistry, Faculty of Science, Kasetsart University, Thailand
2

3

Center of Nanotechnology, Kasetsart University, Thailand

Functional Compounds Special Research Unit (FCSRU), Kasetsart University, Thailand,

The absorption and emission properties of F, OH and NO2 substituted at ortho-, meta-,
and para-positions of cinnamate derivatives were investigated by using the density functional
theory (DFT) and time-dependent DFT (TD-DFT) calculations. The ground (S0) and excited(S1) state geometries were obtained at the B3LYP/6-31G(d) and TD-B3LYP/6-31G(d)methods, respectively. Based upon the optimized structures of the S0 and S1 states, the TDB3LYP/6-311G(d,p) calculations were performed to compute the absorption and emission
energies of the various substituted cinnamates. The results shown that all compounds had the
local minimum at the planar structure conformation except for the NO2 substituted at orthoposition. In the S1 geometry, the bond length alternation (BLA) values of F and OH
compounds decreases correspond to a fully delocalized electronic system, whereas, those of
NO2 increases indicate high delocalization degree of S-bond along the molecules. The
calculated absorption and emission spectra in gas phase and methanol were agreed well withthe experimental spectrum. The main electronic transition of cinnamates at ortho- and metapositions of F and OH substitution correspond to the electronic excitation from HOMO-1 to
LUMO. Whereas, those of NO2 substitution correspond to the electronic excitation form
HOMO to LUMO+1. In addition, the main electronic transition of cinnamates at parapositions of F, OH and NO2 substitution correspond to the electronic excitation from HOMO
to LUMO. Moreover, the predicted radiative lifetimes of cinnamate derivatives which discuss
the origin of the stoke shift were also investigated. Our TD-DFT investigation can provide a
useful insight into the optical and electronic properties of these molecules and a useful toolfor designing and developing the novel UV absorbers.
Keywords: Cinnamate, Density functional theory (DFT), Time-dependent DFT (TD-DFT)[1] Karpkird, T.M., S. Wanichweacharungruang and B. Albinsson. Photochem. Photobiol.
Sci. 2009, 8(10), 1455.
[2] Promkatkaew M., S. Suramitr, T.M. Karpkird, S. Namuangruk, M. Ehara, and S.
Hannongbua. J. Chem. Phys. 2009, 131, 224309-1.
[3] Suramitr S., W. Meeto, P. Wolschann and S. Hannongbua. Theor. Chem. Acc. 2010, 125,
35.

216

7B2-1I

Properties of hollow molecules containing a double core hole,probed by single-photon double ionization
P. Lablanquie1, F. Penent1, J. Palaudoux1, L. Andric1, P. Selles1, S. Carniato1,
K. Bučar2, M. Žitnik2, M. Huttula3, J. H. D. Eland4, E. Shigemasa5, K. Soejima6,
Y. Hikosaka6, I. H. Suzuki7, M. Nakano7, and K. Ito7
1

LCP-MR, CNRS & Université P. et M. Curie, 11 rue P. et M. Curie, 75231 Paris Cedex 05, France
2Jožef Stefan Institute, P. O. Box 3000, SI-1001 Ljubljana
3
Department of Physical Sciences, University of Oulu, Box 3000, 90014, Oulu, Finland4
Department of Chemistry, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
5
UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
6
Department of Environmental Science, Niigata University, Niigata 950-2181, Japan
7
Photon Factory, Institute of Materials Structure Science, Oho, Tsukuba 305-0801, Japan

Although hollow atoms were known and observed for a long time, it is only
very recently that experimental observation of hollow molecules (N2) was possible thanks to sequential inner-shell ionization using x-ray free electron laser [1].
We have demonstrated [2] that such double core hole states can also be studied indetail by single photon double core ionization using synchrotron radiation, even if
the associated double photoionization cross section is extremely weak.
The experiments were performed on BL-16A beamline at Photon Factory (Japan) and on TEMPO beamline at SOLEIL (France) using a magnetic bottle timeof-flight spectrometer.
We studied N2, O2, CO and CO2 molecules. The formation and decay process
is the following:hQ + M → M2+ (K-2) + 2 e-Photoelectron(1a)→ M3+ (K-1v-2) + e-Auger Hypersatellite (1b)→ M4+ (v-4) + e- Auger Satellite, (1c)where v designates a valence shell, and the emitted Auger electrons are called‘hypersatellite’ or simply satellite, depending on whether the K-shell is filled in
the presence of a second K hole or of valence holes. The hypersatellite Auger
electron line has higher energy than the main Auger line associated with single
K-shell ionization, and is characteristic of double K-shell ionization. By detecting
in coincidence all four electrons released in the process (1), we have been able tocharacterized double core-hole states with two K-shell vacancies on the same atom and their satellites. We deduced in this way the binding energy of N22+ (K-2)
states (and their satellites), their respective Auger decay paths and their relative
intensity with respect to N2+ (K-1) states. Single photon double ionization in the Kshell (K-2) represents a small fraction (10-4 to 10-3) of single K-shell ionization for N2,
O2, CO and CO2 molecules. In N2, we could set an upper limit of 1.2% for the 2-site
double K-shell ionization (K-1K-1) on neighbor atoms compared to 1-site (K-2).
These results raise important questions for the theoretical description of the formation,
spectroscopy and decay mechanism of the highly excited species involved. We will alsopresent at the conference our most recent results on 1-photon double K-shell ionization.
[1]. L. Young et al., Nature (London) 466, 56 (2010).
[2]. P. Lablanquie et al., Phys. Rev. Lett. 106, 063003 (2011).

217

7B2-3C

Ionization of Helium in Strong XUV Laser Pulses  a
Theoretical Simulation
Petra Ruth Kapr-  1,2 and Jan    1,2
1
J. Heyrovsky Institute of Physical Chemistry AS CR, v.v.i., Dolejkova 3, 18223 Prague,
Czech Republic
2
Institute of Physics AS CR, v.v.i., Na Slovance 2, 18221 Prague, Czech Republic

I. Introduction
The work presented is part of study of mechanisms of gas ionization in laser sparks.
In our model, isolated gas molecules interact with laser field with a wavelength of
50 nm and the intensity of the tens of TW cm-2. This process is studied for different
lengths of pulses, from short femtosecond pulses to picosecond pulses. We calculate thepopulations of excited states of the emerging helium cation.
II. Details of the theoretical methods
The theoretical description, being at ab initio level, is based on the classical dipole
approximation. The ionization effect is numerically secured by using the complex
scaling transformation. Time-dependent wavefunction of helium atom interacting withthe laser pulse is calculated beyond the adiabatic Floquet approximation, using an
expansion in the basis set of time-dependent Floquet states. The Floquet energies andcoupling elements between the Floquet states are calculated for several field intensities
spanning from zero to the peak intensity of the laser pulse, prior to the non-adiabatic
propagation. The Floquet states are defined in the basis set of primitive dressed states(defined as the direct product of the complex scaled field-free states of helium andphoton states), where the field-free states of helium are obtained using the full CI
method. An extensive basis set of even tempered Gaussians, which is carefully
converged with respect to the complex Floquet energies, is used.

218

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7B3-3C

Nonadiabatic Reactions Studied by Automated Reaction Path
Search Methods
Satoshi Maeda,1,2 Hongyan Xiao,2 Ryo Saito,2 Keiji Morokuma2,31
The Hakubi Center, Kyoto University, Kyoto 606-8302, Japan
2
Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan3
Department of Chemistry and Cherry L. Emerson Center for Scientific Computation,
Emory University, Atlanta, GA 30322.
Introduction. Nonadiabatic transition plays a key role in many chemical reactions.1 It
takes place efficiently within a seam of crossing hypersurface in which two adiabatic
potential energy surfaces (PESs) cross. In many kinetic studies, minimum structures on
the seam of crossing (MSX) have been searched as critical points of nonadiabatic
transition. However, some key MSX structures with highly unexpected geometries arevery difficult to guess, which makes their geometry optimizations very difficult. Hence,
we have developed automated methods for finding unknown/unexpected MSX
structures systematically.2,3 In this talk, these methods are introduced and applied tosearches for photodissociation pathways of NO3 and for ignition pathways of
unsaturated hydrocarbons.4,3Methods. We have developed two methods to explore reaction pathways on single PESs
automatically: the global reaction route mapping5 (GRRM) method and the artificial
force induced reaction6 (AFIR) method. These two are independent but complementallyto each other. Reaction pathways of type A ĺ X (+ Y) can be explored by the GRRM
method, while the AFIR method can search for those of type A + B ĺ X (+ Y). In MSX
searches, these methods are applied to a model function on which approximate MSX
structures are obtained as local minima; many (true) MSX structures can finally beobtained by geometry optimizations starting from such approximate MSX structures.2,3Results. Figure 1 shows an excited state roaming O atom path, in which one of O atoms
in NO3 partially dissociates on the first excited doublet (D1) PES and then roams aroundthe NO2 fragment before producing O2 and NO
on either the D1 or the ground (D0) state PESs.4
This mechanism, which was revealed by the
GRRM method, explains a recent experimental
result.7 New nonadiabatic ignition pathways of
unsaturated hydrocarbons discovered by the
Figure 1. The excited state roaming path
AFIR method are also presented.3
discovered for photodissociation of NO3.

[1] Nanbu, S.; Ishida, T.; Nakamura, H. Chem. Sci. 2010, 1, 663. [2] Maeda, S.; Ohno, K.;
Morokuma, K. J. Phys. Chem. A 2009, 113, 1704. [3] Maeda, S.; Saito, R.; Morokuma, K. J. Phys.
Chem. Lett. 2011, 2, 852. [4] Xiao, H.; Maeda, S.; Morokuma, K. (submitted). [5] Ohno, K.; Maeda,
S. Phys. Scr. 2008, 78, 058122. [6] Maeda, S.; Morokuma, K. J. Chem. Phys. 2010, 132, 241102. [7]Grubb, M. P.; Warter, M. L.; Suits, A. G.; North, S. W. J. Phys. Chem. Lett. 2010, 1, 2455.

220

7B3-4I

Strong and Weak Coordinates within the Context
of the Multi-Coordinate Driven Algorithm
Chin Hui Yu
Department of Chemistry, National Tsing Hua University, 30013 Taiwan
The multi-coordinate driven (MCD) algorithm [1] is the application of a simple
gradient search algorithm to a reaction path problem. A central part of the MCD
algorithm is the differentiation between driving and driven geometry coordinates.
Driving coordinates are used to expand the energy of the system in a Taylor series at
any given point of the reaction path. The MCD algorithm picks the next step into thedirection of the slowest ascent or steepest decent based on the conditions. The driven
coordinates, which are the majority, are optimized as usual within the molecular
framework as defined by the driving ones. The MCD algorithm follows a minimum
work path on the potential energy surface of the system. The choice of the reaction
pathway to be explored is determined by the selection of the driving coordinates.
Therefore, the MCD algorithm can be used to search for unknown products andtransition states starting form a minimum energy structure while keeping thecomputationally expensive Hessian matrix at a minimum size.
Problems arise when weak and strong coordinates are mixed in the set of driving
coordinates. Weak coordinates have small gradients and small force constants. Theenergy penalties for changes in weak coordinates are low during the energetic climb
phase of the search. As the MCD search algorithm follows the path of the smallest
energy increase, weak coordinates tend to dominate the energetic uphill search. For
example, one of the driving coordinates can lead to a change of the molecularconformation away from the investigated reaction path and ultimately to unphysical
jumps in the energetic profile of the system. Several methods, such as dynamic step
size control, harmonic and anharmonic corrections to the energy prediction, external
optimization steps, and on the fly path analysis are applied to resolve this problem. The
application of the aforementioned methods to chemical reactions are investigated, too. It
is discovered that the handling of three groups of coordinates instead of the driving anddriven two originally defined in the MCD algorithm greatly simplifies the application of
the MCD algorithm to chemical reactions.

[1] Berente; G. Náray-Szabó J. Chem. Phys. A 113 (2006) 772.

221

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Dominant reaction pathways of macromolecules:
from classical to quantum mechanical calculations
Pietro FaccioliInterdisciplinary Center for Computational Science (LISC)
Physics Department of Trento University

The investigation of the kinetics of thermally activated reactions by means of Molecular Dynamics (MD) simulations
is very inefficient, because most of the computational time is wasted to simulate the exploration of the (meta-) stablestates and because the internal dynamics of macromolecules is characterized by widely decoupled time scales. In thisseminar, I will discuss how such problems are rigorously bypassed in the recently developed Dominant Reaction
Pathways (DRP) approach [1, 2, 3]. As an illustrative example of application, I will report on the first calculation of thedominant folding pathways of a peptide, based on ab-initio electronic structure calculations, rather than on an empiricalforce field [4]. Very recently, the DRP method has been upgraded to systematically include also the quantum corrections
to the diffusive motion of the atomic nuclei [5]. We have found that such corrections are quite large and give raise tosome counter-intuitive phenomenology.
References:
1. P.Faccioli, M.Sega, F.Pederiva and H.Orland, Phys. Rev. Lett. 97 (2006), 108101. M.Sega, P.Faccioli, F.Pederiva, G Garberoglio and H.Orland,
Phys. Rev. Lett. 99 (2007), 118102. E.Autieri, P.Faccioli, M.Sega, F.Pederiva and H.Orland, , J. Chem. Phys. 130 (2009) 064106.
2. P.Faccioli, Jour. of Phys. Chem. B112 (2008) 13756. P. Faccioli, A. Lonardi and H.Orland, J. Chem Phys., 133 045104 (2010)
3. S. a Beccara, G. Garberoglio, P.Faccioli and F. Pederiva, J. Chem. Phys. 132 (2010), 111102 (top of the list in the Editors’ choice for best JCP
communications of the year)
4. S. a Beccara, P.Faccioli , G. Garberoglio, M.Sega, F. Pederiva and H. Orland, Journ. Chem. Phys. 134 024501 (2011) (selected for journal cover)
5. S. a Beccara, P. Faccioli and G. Garberoglio, preprint: arXiv:1012.3308

222

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A first-principles density functional
approach for charge transfer & transport
Roi Baer(1), Ester Livshits(1), Tamar Stein(1), Adva Baratz(1), Michael Galperin(2) and Leeor Kronik(3)(1) Fritz Haber Center for Molecular Dynamics, Chaim Weizmann Institute of Chemistry, The Hebrew
University of Jerusalem, Jerusalem, Israel.
(2) Department of Chemistry, University of California at San Diego, USA(3) Department of Materials and Interfaces, The Weizmann Institute of Science, Rehovoth Israel
Abstract:
We present a first-principles density functional theory (DFT) which is successful in classes of problems
traditionally considered "too tough for DFT". The basic elements of this method are briefly reviewed(first principles tuning of the Baer-Neuhauser-Livshits range-separated hybrid), but the focus is on
recent applications. Unlike most DFT approximations, our approach yields orbital energies that closely
approximate the ionization potentials and electron affinity of atoms, molecules, clusters and solids. We
demonstrate the success of the method in treating the breaking of 3 electron bonds and reaction
barriers. The time-dependent version of the method falls within the Runge-Gross TDDFT framework,
using generalized time-dependent Kohn-Sham equations. The method is capable of describing Rydberg
and electron-transfer excitations. We give examples with comparison to experiment on coumarin dyes,
aromatic molecular complexes and bipeptides. Finally, we discuss an application to molecularelectronics, where a gate potential tunes the conductance level of a molecular junction. Concepts suchas Coulomb blockade and exciton binding energy are clearly illustrated using the orbital energies of our
first principles DFT method.
Literature:(1) R. Baer, E. Livshits, and U. Salzner, "“Tuned” Range-separated hybrids in density functional
theory", Ann. Rev. Phys. Chem. 61, 85-109 (2010).
(2) E. Livshits and R. Baer, "A Density Functional Theory for Symmetric Radical Cations from Bonding
to Dissociation", J. Phys. Chem. A 112, 12789-12791 (2008).
(3) T. Stein, L. Kronik, and R. Baer, "Reliable Prediction of Charge Transfer Excitations in MolecularComplexes Using Time-Dependent Density Functional Theory", J. Am. Chem. Soc. 131, 28182820 (2009).
(4) T. Stein, L. Kronik, and R. Baer, "Prediction of charge-transfer excitations in coumarin-based dyes
using a range-separated functional tuned from first principles", J. Chem. Phys. 131, 244119-5(2009).
(5) U. Salzner and R. Baer, "Koopmans' springs to life", J. Chem. Phys. 131, 231101-4 (2009).
(6) H. R. Eisenberg and R. Baer, "A new generalized Kohn-Sham method for fundamental band-gaps
in solids", Phys. Chem. Chem. Phys. 11, 4674-4680 (2009).
(7) T. Stein, H. Eisenberg, L. Kronik, and R. Baer, "Fundamental gaps of finite systems from theeigenvalues of a generalized Kohn-Sham method", Phys. Rev. Lett. 105, 266802 (2010).

223

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Better Ways to Get Excited States and Reaction Barriers From DFT
Troy Van Voorhis
Department of Chemistry
Massachusetts Institute of Technology
77 Massachusetts Ave.
Cambridge, MA 02139

Density functional theory (DFT) is the de facto standard for simulating the electronic
ground state near equilibrium. At the same time, standard functionals have some welladvertised problems in dealing with electronic excited states and molecules that are near
the transition state region. In this talk we show that, in many cases, the problem isn’t asmuch that DFT gives the wrong answer as that electronic structure theorists insist on
asking the wrong questions. Using chemical intuition, one can often choose initial andfinal states lead to accurate predictions (via cancellation of errors) even in cases where
DFT nominally fails. For example, applying constraints to the charge density leads toreliable electron transfer energies; ∆SCF calculations give accurate results for valenceand Rydberg excitations; localized charge states provide a basis for improving reaction
barrier heights; configuration interaction based on a DFT active space gives aqualitatively correct description of conical intersections between ground and excitedstates. Time permitting, we will discuss how these developments could be leveraged to
improve existing functionals.

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Recent progress in long-range corrected density functional theory
Takao Tsuneda1
1
Fuel Cell Nanomaterials Center, University of Yamanashi, Japanttsuneda@yamanashi.ac.jp
Recent studies on long-range corrected (LC) density functional theory (DFT) [1]and its applications are presented.
So far, it has been reported that LC-DFT solves or clearly improves various
properties that conventional DFTs have seriously failed to reproduce: e.g. van der
Waals and other weak bond energies and structures [2], optical properties of longchain molecules [3] and diradicals [4], and charge transfer energies and oscillator
strengths in time-dependent DFT (TDDFT) [5]. In particular, it was recently foundthat LC-DFT quantitatively reproduces valence orbital energies for the ﬁrst time[6]. We have recently suggested that several properties are unexpectedly poorly
reproduced are clearly improved by using LC-DFT. In this talk, I will introduce
these properties and will explain why these are signiﬁcantly improved by LC-DFT.
However, there remains several serious problems that cannot be solved even
by LC-DFT. We have worked on ﬁnding out these problems and have suggested
new approaches to solve them. For example, we found that long-range correction
hardly aﬀects core excitation energies in TDDFT that have been signiﬁcantly underestimated in TDDFT even using up-to-date functionals. To improve these core
excitation energies, we have therefore suggested a regional self-interaction correction
method, in which short-range exchange functionals in the regions of self-interacted
electrons are only replaced with Hartree-Fock exchange integral based on the pseudospectral method. We have also made it possible to calculate spin-orbit splittings ofexcitation energies in TDDFT by implementing spin-orbit couplings into TDDFT
program. I will brieﬂy review these correction methods for LC-DFT in this talk.
[1] H. Iikura, T. Tsuneda, T. Yanai, and K. Hirao, J. Chem. Phys. 115, 3540 (2001).
[2] M. Kamiya, T. Tsuneda, and K. Hirao, J. Chem. Phys. 117, 6010 (2002); T.
Sato, T. Tsuneda, and K. Hirao, J. Chem. Phys. 126, 154105 (2007).
[3] M. Kamiya, H. Sekino, T. Tsuneda, and K. Hirao, J. Chem. Phys. 122, 234111(2005).
[4] R. Kishi, S. Bonness, K. Yoneda, M. Nakano, E. Botek, B. Champagne, T. Kubo,
K. Kamada, K. Ohta, and T. Tsuneda, J. Chem. Phys. 82, 094107 (2010).
[5] Y. Tawada, T. Tsuneda, S. Yanagisawa, T. Yanai and K. Hirao, J. Chem. Phys.
120, 8425 (2004).
[6] T. Tsuneda, J.-W. Song, S. Suzuki, and K. Hirao, J. Chem. Phys. 133, 174101(2010).

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Improved DFT from Electrons on a SpherePeter M.W. Gill,1 Pierre-François Loos,2Research School of Chemistry, Australian National University, Australia
Density functional theory (DFT) is now popular within the chemical physics
community, but it still suﬀers from some serious deﬁciencies and most of these are
now well understood [1]. One of the key goals of modern research, therefore, is todevelop new methods that preserve the low cost of DFT calculations while oﬀeringsigniﬁcantly enhanced accuracy.
Many of the weaknesses of DFT stem from the fact that most functionals are
based on the uniform electron gas, a model consisting of an inﬁnite number ofelectrons in an inﬁnite volume. Unfortunately, this system does not resemble theelectron density in most molecules and one route to the improvement of DFT is toreplace this foundation with a new one.
In recent years, there has been growing interest in the quantum mechanics ofpairs of conﬁned electrons. The helium atom, of course, has been studied fromthe early days and the Hooke’s Law atom was introduced in the 1960s. But, more
recently, accurate solutions have also been found for pairs of electrons trapped inside
a ball [2] and on its surface [3–8] and these are now being used for the developmentof new functionals in density functional theory (DFT).
The electrons-on-a-sphere model is particularly attractive because it is deﬁned
by a single parameter (the radius R of the sphere) and varying this takes us froma weakly correlated system (small R) dominated by dynamical correlation, to astrongly correlated system (large R) dominated by static correlation.
I will review this model and show how it can be used as the starting point for a
new way of understanding and improving DFT.
[1] A Cohen, P Mori-Sanchez and W Yang, Science 321 (2008) 792[2] PF Loos and PMW Gill, J Chem Phys 132 (2010) 234111[3] PF Loos and PMW Gill, Phys Rev A 79 (2009) 062517[4] PF Loos and PMW Gill, Phys Rev Lett 103 (2009) 123008[5] PF Loos and PMW Gill, J Chem Phys 131 (2009) 241101[6] PF Loos and PMW Gill, Mol Phys 108 (2010) 2527
[7] PF Loos and PMW Gill, Chem Phys Lett 500 (2010) 1[8] PF Loos and PMW Gill, Phys Rev B, submitted

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7C2-3C
Electronic structure calculations of spherically confined N  1 electron atoms
K.D.SenSchool of Chemistry, University of Hyderabad
Hyderabad 500046, India
Following the exact results [1] on the confined one electron systems which highlight thenovel spectral-features arising due to the spherical confinement we proceed to present
the state of art calulations for the confined N-electron atoms. Radial, angular and total
correlation energies are calculated [2] for four different two-electron systems withatomic numbers Z = 0 - 3 confined within an impenetrable sphere of radius R. We
report accurate results for the non-relativistic, Hartree-Fock and radial limit energies
over a range of confinement radii from 0.05 - 10 a0. At small R, the correlation energies
approach limiting values that are independent of Z while at intermediate R, systems
with Z > 1 exhibit a characteristic maximum in the correlation energy resulting from anincrease in the angular correlation energy which is offset by a decrease in the radial
correlation energy. The correlation calculations are reported with the 70 term Hylleraas
expansion in s, t and u. We also report [3] a new expression for the expectation value
integral of Hermitian operators for spherically-symmetric states in Hylleraas
coordinates for the Helium atom confined in a cavity with infinite potential barrier
walls. The expression is comprised of two components spanning different domains ofspace which is shown to be a third faster than the conventionally employed expression
for confined systems derived by ten Seldam – de Groot [4]. It is further shown that in
the limit of the free Helium atom, our expression for well-behaved wave functions isequivalent to that originally derived by Hylleraas. Finally, we shall present accurate
Hartree-Fock estimates of the critical radius [5] for the spherically confined atoms in the
periodic table. The critical radius is defined as the radius of the impenetrable sphericalcavity at which the highest occupied orbital of the confined atom corresponds to a zero
eigenvalue and its estimates provide a new set of characteristic data relating to theelectronic structure of atoms. Finally, we present accurate computations [6] of static anddynamic dipole polarizabilities for the ground and excited states of hydrogen atom
confined at the center of multiwalled fullerene cage, using the Galerkin variational
method developed on a B-spline basis set. It is shown that the addition of new walls
does not modify the polarizability of the ground state, but significantly modifies thoseof the excited states. A condition on the ratio of the scaled second derivative of density
to the scaled density evaluated at the nuclear position is tested in case of the cage
confined atoms for the first time and the significance of such numerical results are
discussed. Similar results of scaled density at the nucleus in case of hydrogen atom inpresence of ultra-high magnetic fields as those present in the neutron stars have been
performed using the Lagrange mesh [7] to provide a measure of the non-sphericity ofelectron in the vicinity of the nucleus.
[1] K.D. Sen, V. I. Pupyshev, and H. E. Montgomery Jr. , Adv. Quantum Chem. 57,
25 (2009).
[2] C.E. Wilson, H.E. Montgomery, Jr., K.D. Sen and D.C. Thompson, Phys. Lett. A 374,441 (2010).
[3] Xiao-Yin Pan , Viraht Sahni , Lou Massa , and K.D. Sen (To be published).
[4] C. A. ten Seldam and S. R. de Groot , Physica. 18, 891 (1952).
[5 ] Y.P. Varshni, J. Phys. B: At. Mol. Opt. Phys. 31, 2849 (1998).
[6 ] O. Motapon, S. A. Ndengue and K.D. Sen , Intl. J. Quantum Chem. (2010).
[7 ] D. Baye and K.D. Sen , Phys. Rev. E 78, 026701 (2008) ;K.D. Sen (To be
published) .

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Towards an order N scaling force field with an accurate treatment of
many-body dispersion and polarization
Glenn J. Martyna1,2 and Andrew Jones2
1
Physical Science, IBM Research, IBM TJ Watson Lab, Yorktown Heights, NY ,USA
2
School of Physics,University of Edinburgh, Edinburgh, UK
There are many physical systems where the non-pairwise additive nature of polarizationand dispersion interactions becomes very important, in particular, the complex
heterogeneous systems of interest in chemistry, biology and physics. For example, thedipole moment of water changes from 1.85 Debye in the gas phase to approximately 2.6
Debye in the bulk liquid and attains intermediate values at hydrophobic interfaces due
to many-body polarization. Similarly, although the bulk properties of hydrophobic
fluids can be modeled using a pair potential, this underestimates the surface tension by
30% due to many-body dispersion interactions. In order to model both the fullmany-body polarization and dispersion interactions in atomic and molecule systems, asystem of quantized Drude oscillators is introduced and a O(N) simulation method
based on quantum path integrals is described using diagramatic expansions of the
propagator. Applications to simple, xenon, and more complex systems, water, are given.

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Development of the Explicit Solvation Shell Model
Eirik F. da Silva,1 Kenneth M. Merz2
1
Department of Process Technology, SINTEF Materials and Chemistry,
7465 Trondheim, Norway
2
Quantum Theory Project, University of Florida, Gainesville, Florida 32611

I. Introduction
Accurately calculating the free energy of solvation is a long-standing challenge incomputational chemistry. Predictions of the free energy of solvation for ions are
particularly challenging. The most widely used models for such calculations arecontinuum solvation models. A key limitation is that they can not capture specificchemical features of solute-solvent interactions. One approach to get around thislimitation is to add solvent molecules in the continuum calculations. The explicit
solvation shell (ESS) model [1] is based on this approach. The present paper reports arefinement of the model and application to calculation of base strength.
II. Methods
In the ESS model solute-solvent clusters are extracted from liquid simulations.
Calculations are carried out on an ensemble of a 100 clusters, the calculations being
based on linear averaging of energies from the clusters. In the present version of themodel 5 solvent water molecules are included for all solutes. Cluster calculations arecarried out at the HF/6-31+G(d) level and the continuum model utilized is the
Poisson-Boltzmann model implemented in the DIVCON code.
The refinement in the model consists in adding a correction term proportional to thesurface area of the cluster.
In calculations of amine base strength the ESS model were utilized to calculate thesolvation energy of the protonated species. Gas-phase base strengths were carried out
with the CBS-QB3 method, while solvation energies for the neutral species were
calculated with the SM8 solvation model.
III. Results
Ion solvation energies were calculated for 33 cations and 33 anions. The average
unsigned error was 2 kcal/mol for both anions and cations. Base strengths were calculated
for 23 species, the unsigned average error was in this case 1.4 pKa units. We believe theseare very encouraging results, particularly for a model that has no tunable parameters.

[1] Eirik F. da Silva; Hallvard F. Svendsen; Kenneth M. Merz Jr. J. Phys. Chem. A
2009, 113, 6404-6409.

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Ab Initio Composite Methods: Beyond Ground State
Main Group Species
Angela K. Wilson, Wanyi Jiang, Marie Laury, John Determan,
Charles Peterson, and Gbenga Oyedepo
Department of Chemistry and Center for Advanced Scientific Computing and Modeling,
University of North Texas, Denton, Texas, 76203-5070, U.S.A.
Ab initio composite methods provide a powerful means to address thermochemical properties ofmain group species. Despite their tremendous popularity, there has been limited application ofthese methods beyond ground state main group species. Several years ago, we introduced thecorrelation consistent Composite Approach (ccCA) as an approach that was not only able toaddress main group chemistry, but also could address transition metal chemistry. A similar
algorithm of multireference methods, the multireference correlation consistent Composite
Approach (MR-ccCA), was developed to address problems for which a single reference
wavefunction may not be suitable, such as for excited states and bond formation anddissociation. As well, because of the synergy of the steps within MR-ccCA, the method has
been effective in the prediction of potential energy surfaces.
Recent developments for ccCA and MR-ccCA are discussed, including developments andsuccesses for transition metal chemistry, where ccCA provides a powerful gauge of theperformance of density functional approaches, particularly in the absence of experimental data.
Over 200 transition metals species have been investigated, and over a thousand main groupspecies have been investigated, ranging from weakly to tightly bound systems. Overall, ccCA is
one of the most effective ab initio composite methods available.

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