Abstracts of Invitedand Contributed Talks, Sep. 8233

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Theoretical Studies on Photoinduced Charge Separation of
Molecular Hetero-Junction and Dye-Sensitized Solar Cells
Koichi Yamashita
Department of Chemical System Engineering, The University of Tokyo,113-8656 Tokyo, JapanI will discuss our theoretical studies on the optical and electronic process that take place in organic
solar cells. First, in order to obtain the design rules of conjugated polymer required for improved
molecular electronics, the charge transport properties at different organic-organic semiconductor
interfaces (TFB/F8BT) are studied based on ab initio quantum master equations. The results suggest
a mechanism of exciton-migration followed by a hole back transfer addition to a simple
charge-transfer, which leads to a red-shifted and longer-lived emission of F8BT. Secondary, I will
discuss about several new transitions due to the interfacial charge transfer found for the TCNE/TiO2
dye-sensitized solar cells. The surface complex of TiO2 nanoparticles and TCNQ are studied based on
DFT calculations and the structure of the surface complex optimized shows an IR spectrum analogous
to the experimental spectrum. From TDDFT calculations based on this optimized structure, we showthat the interfacial charge transfer transitions from the HOMO of the surface-bound TCNQ molecules
to the unoccupied levels of the TiO2 nanoclusters occur in the visible to near IR region. Finally,
recombination in dye-sensitized solar cells with direct injection which is cast as internal conversion
will be discussed. For catechol-thiophene dyes with 1, 2, or 3 thiophene units, the complex
reproduces the previously observed dye-to-semiconductor bands. Based on ab initio calculations, we
compare the decomposition of the internal conversion rate by vibrational mode and predict a trend inrecombination with the extension of conjugation, which offers an explanation for the trend in DSSC
efficiency.

We

also

analyzederivative(2E,4E-2-cyano-5-(4-dimethylaminophenyl)

coupling

constants

penta-2,4-dienoic

acid)

in

dyes

NK1

and

NK7

(2E,4E-2-cyano-5-(4-diphenylaminophelyl) penta-2,4-dienoic acid) and relate them to the different
dynamics that was observed for these dyes on TiO2.
References[1] ”Theoretical Study of the Surface Complex of TiO2 and TCNQ: Interfacial Charge Transfer
Transitions”, Ryota Jono, Jun-ichi Fujisawa, Hiroshi Segawa, Koichi Yamashita, J. Phys. Chem.
Lett., 2, 1167-1170 (2011).
[2] “Derivative coupling constants of NK1, NK7 dyes and their relation to excited state dynamics insolar cell applications”, Sergei Manzhos, Hiroshi Segawa, and Koichi Yamashita, Chem. Phys.
Lett, 501, 580-586 (2011).
[3] “A model for recombination in Type II dye-sensitized solar cells: catechol-thiophene dyes”, Sergei
Manzhos, Hiroshi Segawa, Koichi Yamashita, Chem. Phys. Lett. 504, 230-235 (2011).

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Orbital theories for molecular electronic devices
Matthias Ernzerhof
Department of Chemistry, University of Montreal, Canada

Ballistic electron transport through molecules occurs, for instance, in molecularelectronic devices (MEDs). In MEDs, two external contacts are connected to a moleculeand the current is measured as a function of the applied voltage. Ballistic transport ischaracterized by the absence of coupling between electronic and nuclear degrees of
freedom so that the coherence of the electronic wave function is preserved across themolecule. Theories of MEDs are quite involved in general, requiring advanced Green’s
function techniques. However, various prominent features of MEDs can be understooddrawing only on elementary quantum theory. To support this point of view, we discuss
simple models [1-4] which enable one to reproduce and predict key features of MEDs.
We present, for example, a two component orbital theory. In this theory, the device
orbitals (DOs) are written as a two component wave function, each of which is much
simpler to construct than the combined orbital. Using these DOs, the conductance can becalculated drawing on the source-sink potential approach [1]. To illustrate our theory,
we apply it to explain the conductance suppression in cross-conjugated systems and thedependence of the conductance on the contact position in aromatic systems. Furthermore,
we apply our models to analyze the conductance of finite graphene flakes of varying
shapes and sizes. We establishing simple concepts relating the structure of the graphene
flakes to their conductance.
[1] F. Goyer, M. Ernzerhof, M. Zhuang, J. Chem. Phys. 126, 144104 (2007).
[2] M. Ernzerhof, J. Chem. Phys. 127, 204709 (2007).
[3] M. Ernzerhof, F. Goyer, J. Chem. Theory Comput. 6, 1818 (2010).
[4] M. Ernzerhof, J. Chem. Phys., submitted.

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Molecular electronics and ultrafast DNA sequencing
1

Seung Kyu Min,1 Kwang S. Kim1
Department of Chemistry, Pohang University of Science and Technology, Pohang
790-784, Korea

Delicate modulation of the molecular orbitals in molecular systems is useful to tune theperformance of electron/spin transport. Not only electric and magnetic fields are
powerful means for that purpose but also the characteristic change in conductance due tointermolecular interactions such as pi-pi stacking can be utilized for molecular sensing.
Thus, we discuss the effects of external fields on molecular electronic and spintronic
devices. Electron/spin transport phenomena in molecular electronic/spintronic devices[1] and graphene nanoribbon spin valves [2] are discussed based on density functional
theory (DFT) coupled to non-equilibrium Green function theory (NEGF). The
non-collinear spin states for the open systems are fully taken into account in aself-consistent manner with the non-equilibrium Green’s function approach by using the
Postrans program package [1-3]. A graphene nanoribbon (GNR) spin-valve device shows
the super magnetoresistance behavior as a spin filter which selectively transmits almost
100% spin-polarized current [2]. Given that GNR electrodes show pristine molecularcharacteristics much better than Au or Ru electrodes [4], we find that measuring
two-dimensional conductance spectra of a graphene [5] or GNR placed across a fluidic
nanochannel leads to a powerful ultrafast DNA sequencing method [6]. In this device,while a single-stranded DNA (ssDNA) passes beneath the GNR, a single base interacts
with the GNR via π-π stacking, giving a sharp conductance change. To explain theoperation principle for sequencing the target ssDNA bases, we performed four steptheoretical calculations. First, the binding energies between each DNA base and GNR are
investigated from ab initio quantum chemical calculations. Second, the molecular
dynamics study was performed in the realistic manner including the temperature effects,
solvent molecules, and counter ions. Third, the electron transport properties of DNA
base-GNR complex are studied by the DFT-NEGF method to understand the origin of
conductance differences between DNA bases. Finally, we clarified the sequence of thetarget ssDNA via our data-mining technique and two-dimensional transient
autocorrelation functions. This reliable ultrafast sequencing method would revolutionize
the future bioinformatics and genetics.
[1] W. Y. Kim et al. Acc. Chem. Res. 43, 111 (2010).
[2] W. Y. Kim et al. Nature Nanotech. 3, 408 (2008).
[3] W. Y. Kim et al. J. Comput. Chem. 29, 1073 (2008).
[4] Y. Cho et al. J. Phys. Chem. A 113, 4100 (2009).
[5] K. S. Kim et al. Nature 457, 706 (2009).
[6] S. K. Min, et al. Nature Nanotech. 6, 162 (2011).

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Oxidative dehydrogenation of a terminal waterat the rutile TiO2 (110)-water interface
Jun Cheng,1 Marialore Sulpizi1,2 , Joost VandeVondele 3 Michiel Sprik,1
1
Department of Chemistry, University of Cambridge, United Kingdom
2
Department of Physics, Mainz University, Germany
3
Physical Chemistry Institute, University of Zurich, Switzerland
Oxidative dehydrogenation (ODH) of a H2 O molecule is enormously costly, taking 2.7 eV. Deprotonation requires 0.8 eV. The diﬀerence is still large enough togive the hydroxyl radical a daunting oxidative power of 1.9 V vs SHE. Will adsorption on a transition metal oxide surface bring the ODH energy down? If so, will
this not also decrease the reduction potential of the adsorbed OH radical product?
We have investigated this question using a combination of density functional theory
based molecular dynamics (DFTMD) and free energy perturbation methods. The
model metal oxide system is the much studied rutile TiO2 (110)-water interface. Using PBE, the surface ODH energy was indeed found to be lower than in solution.
Resolving in a deprotonation and oxidation free energy, revealed that the increasein acidity of a terminal H2 O relative to solution[1] is an important factor in the H2 O
activation. The oxidation potential of the OH radical was found, somewhat surprisingly, to be almost the same. The surface ODH energy is not directly available fromexperiment. We can however use the solution data mentioned above as validation.
Unfortunately our reduction potential of the aqueous OH radical is too small by asmuch as 0.6 V[2]. This eﬀect is now generally understood to be the result of the tendency of the generalized gradient approximation (GGA) to delocalize holes in O2p
orbitals. For the same reason the GGA pushes the valence band maximum in TiO2
up by 0.8 eV[3]. For the surface ODH reaction the delocalization error even leads
to the formation of the wrong species, namely an adsorbed hydroxide anion plus
delocalized hole in the valence band, rather than an hydroxyl radical. These observations cast serious doubt on the PBE results. Only recently we were able to makeprogress thanks to the development of eﬃcient methods for the implementation of
exact exchange under periodic boundary conditions[4]. DFTMD simulation using
the HSE screened hybrid functional, indeed traps the hole with localization energies
of 0.5 eV or more. This talk will be a brief review of our DFTMD methodology
together with the presentation of some of the latest results obtained with HSE.
[1] J. Cheng and M. Sprik, J. Chem. Theor. Comp. 6 (2010), 880.
[2] C. Adriaanse, M. Sulpizi, J. VandeVondele, and M. Sprik, J. Am. Chem. Soc.
131 (2009), 6046.
[3] J. Cheng and M. Sprik, Phys. Rev. B 82 (2010), 081406(R).
[4] M. Guidon, M., J. Hutter and J. VandeVondele, J. Chem. Theory Comput. 6(2010), 2348.

237

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Adsorption and excitation of black-dye on TiO2 anatase (101) surface
for dye-sensitized solar cells
Keitaro Sodeyama,1,2 Masato Sumita,1 Yoshitaka Tateyama1,21International Center for Materials Nanoarchitectonics (MANA), National Institute forMaterials Science (NIMS), Japan
2
CREST and PRESTO, Japan Science and Technology Agency, Japan
Dye-sensitized solar cells (DSSC) are expected as a cost effective next generation
solar-to-electricity energy conversion devices [1]. The efficiency of the power
conversion is greater than 10% when Ru(II) polypyridyl dyes are used and increasing
the efficiency of the DSSC is very important issue as academic and industrial interests.
To understand a photoexcited electron transfer process, an initial step of the energy
conversion of the DSSC, we investigate possible adsorbed structures of black-dye on
TiO2 anatase (101) surface and excited states of the black-dye molecules.
To obtain the adsorbed structures, geometry optimizations were carried out using
DFT method (BLYP functional) with plane wave basis. For excited state calculations ofblack-dye molecule, TDDFT method (B3LYP functional) was used with Gaussian basis.
We considered four possible adsorbed structures, two of them are bound to surface
by one carboxyl group (one-leg) and the other two are bound with two carboxyl groups(two-legs). Regarding the adsorbed structures of Ru(II) polypyridyl dyes such as N3 dye,
three-legs structure with one of a proton of carboxyl groups transferred to surface has
been regarded as a most stable structure rather than one-leg and two-legs structures. In
this study, we found that the one-leg structure with the proton retained on a carboxylgroup of the black-dye was more stable than two-legs structures (Fig. 1). This is
attributed to the presence of the hydrogen bond between hydrogen atom of carboxylgroup and oxygen atom of surface.
We also investigated the excited states of isolated and adsorbed structures of theblack-dye molecules and compared with the UV-visible spectra. In adsorbed structureswith a proton retained on the dye, the planar
structure of the terpyridine ligand was distorted
from the isolated one, causing red shift of theUV-visible spectra. We examined Kohn-Shamorbitals related to the large peaks and found thatthe main configurations of the excited states
were delocalized orbitals on terpyridine ligand.
These delocalized characters are responsible forthe good performance of the Ru(II) polypyridyl
dyes.
Figure 1. Adsorbed structure of[1] O’Regan, B.; Grätzel, M. Nature 1991, 353, black-dye on TiO anatase (101)2surface of one-leg protonated form.
737.

238

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Real-time TDDFT calculation in molecules and solids
Kazuhiro Yabana
Center for Computational Sciences, University of Tsukuba, Japan
We have been developing a computational method to solve the time-dependent
Kohn-Sham equation in real time and real space to describe electron dynamics inducedby optical field. The method may be applied to both isolated molecules and bulk
periodic solids. In the presentation, I would like to present our recent progresses withthe method taking examples from both molecules and solids.
In molecules, we have recently developed a real-time computational method formagnetic circular dichroism (MCD) [1]. In our framework, we solve the time-dependent
Kohn-Sham equation under a finite magnetic field. We may thus obtain the MCD
spectra of both discrete and continuum region without any perturbative expansion.
In periodic solids, we may describe nonlinear electron dynamics in dielectrics
induced by an ultrashort laser pulse. We show our recent application to explore ageneration mechanism of coherent phonon in typical dielectrics, Silicon [2]. It has been
invoked that there are two mechanisms in coherent phonon generation, the impulsively
stimulated Raman scattering induced by a virtual electronic excitation during theirradiation of the laser pulse, and the displacive excitation through a real excitation ofelectrons. We show that the time-dependent density functional theory describes bothmechanisms in a unified way.
[1] K.M. Lee, K. Yabana, G.F. Bertsch, J. Chem. Phys. 134, 144106 (2011).
[2] Y. Shinohara, K. Yabana, Y. Kawashita, J.-I. Iwata, T. Otobe, G.F. Bertsch, Phys. Rev.
B82, 155110 (2010).

239

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Photoinduced Electron Dynamics in Nanostructures:
Nonuniform and Self-Consistent Light-Matter Interactions
Katsuyuki Nobusada
Department of Theoretical and Computational Molecular Science,
Institute for Molecular Science, Japan
In the conventional optical responses of molecules, wavelengths of the lights areusually considered to be much longer than molecular sizes. Thus, a target molecule
is well approximated by a point dipole and the dipole feels an almost uniform electromagnetic ﬁeld. This condition underlies the conventional dipole approximation.
Furthermore, light is an external ﬁeld to excite molecules and its wavelength isdeﬁnitely determined by an apparatus condition. Since spatial resolution of spectroscopy is limited by the wavelength of the incident light, it is impossible to gain
molecular properties in a local region shorter than the wavelength, i.e., diﬀraction
limit. However, recent development of nanofabrication and nano-optical techniques
requires a more general optical response theory fully taking account of nonuniform
and self-consistent light-matter interactions.
First, a generalized theoretical description of a light-matter interaction beyond
a dipole approximation is developed on the basis of the multipolar Hamiltonian
with the aim of understanding the near-ﬁeld excitation in nanostructures[1]. The
theory is formulated for a system consisting of a molecule and a near-ﬁeld, wherea nonuniform electric ﬁeld plays a crucial role. A nonuniform electronic excitationof a molecule is demonstrated by solving a time-dependent Kohn-Sham equation in
real-space and real-time [2,3] with an implementation of the nonuniform light-matterinteraction.
Second, optical forces induced by a near-ﬁeld are calculated for a 1 nm-sized
metal particle mimicked by a jellium model fully taking account of multipole interaction [4]. A highly localized near-ﬁeld nonuniformly polarizes the metal particle.
The locally induced polarization charges in the molecules are partly canceled by
the screening charges. The polarization and screening charges generally contributeto the attractive and repulsive forces, respectively, and a sensible balance between
these charges results in several peaks in the optical force as a function of the frequency of the near-ﬁeld. The resonance excitation does not necessarily maximallyinduce the net force and the force exerted on the molecules strongly depends on thedetails of their electronic structures.
Finally, I will discuss our recent research activity of electron and electromagnetic
ﬁeld coupled dynamics in nanostructures.
[1] T. Iwasa and K. Nobusada,Phys. Rev. A 80, 043409 (2009).
[2] K. Nobusada and K. Yabana, Phys. Rev. A 75, 032518 (2007).
[3] K. Nobusada and K. Yabana, Phys. Rev. A 70, 043411 (2004).
[4] T. Iwasa and K. Nobusada, Phys. Rev. A 82, 043411 (2010).

240

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An efficient non-pairwise-additive correlation energy functional for dispersion forces
John F. Dobson and Tim Gould
We use the continuum mechanics (CM) of Tao, Gao, Tokatly and Vignale [PRL 81,
195106 (2010)] to describe electronic response of inhomogeneous electronc systems
to effective fields. We thereby obtain an approximation to the RPA correlation energythat is computationally efficient and describes long-ranged (e.g. van der Waals)
correlations beyond the pairwise-additive approximation. So far this approach has
been tested successfully on the case of two thin parallel metal slabs at all separations
D down to overlap of the electronic clouds [ArXiv:1106.0327v2]. Our method
reproduced full (d)RPA results well for all D values, and gave the correct asymptote
E = -CD-5/2 at large separations D o f, in contrast to the present generation ofefficient van der Waals functionals. The CM theory also gives the exact response ofquantal one-electron systems. Development of the method for periodic systems isunderway.

241

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Analytic calculations of anharmonic eﬀects in vibrational spectra
Kenneth Ruud,1 Magnus Ringholm,1 Andreas J. Thorvaldsen1 , Bin Gao1 ,R. Bast1 , Dan Jonsson1 ,1
Centre for Theoretical and Computational Chemistry, Department of Chemistry,
University of Tromsø, 9037 Tromsø, Norway
Anharmonic eﬀects are small, but can make important contributions to a wide
range of vibrational spectroscopies. With the advent of nonlinear vibrational spectroscopies, these anharmonic eﬀects can be directly probed [1,2].
Computationally, the calculation of anharmonic corrections to vibrational spectra and nonlinear vibrational spectroscopies is complicated due to the need for calculating higher-order energy derivatives with respect to geometrical perturbations.
Calculations of anharmonic eﬀects are almost exclusively done in a mixed analyticalnumerical scheme [3,4], although an analytic implementation including up to quartic
force constants was presented at the Hartree–Fock level of theory by Handy andcoworkers twenty years ago [5].
In this talk, I will present our recent eﬀorts in obtaining an analytic approach forcalculating the necessary energy derivatives analytically, both at relativistic and nonrelativistic levels of theory [6]. In addition to a brief presentation of the theoreticalframework, I will present sample calculations of anharmonic eﬀects in various linear
and nonlinear vibrational spectroscopies.
[1] S. Mukhamel, Principles of Nonlinear Optics and Spectroscopy, Oxford University
Press (New York), 1995.
[2] S. Hahn, K. Park, and M. Cho, J. Chem. Phys. 111, 4121 (1999).
[3] J. F. Stanton and J. Gauss, Int. Rev. Phys. Chem. 19, 61 (2000).
[4] V. Barone, J. Chem.Phys. 122, 014108 (2005).
[5] P. E. Maslen, D. Jayatilaka, S. M. Colwell, R. D. Amos and N. C. Handy,
J. Chem. Phys. 95, 7409 (1991).
[6] R. Bast, U. Ekström, B. Gao, T. Helgaker, K. Ruud and A. J. Thorvaldsen,
Phys. Chem. Chem. Phys. 13, 2627 (2011).

242

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Anharmonic vibrational theory for large polyatomic molecules
Kiyoshi Yagi and So Hirata
Department of Chemistry, University of Illinois at Urbana-Champaign, U.S.A.
I. Introduction
A combination of the electronic structure and vibrational theories has made feasible
a computation of molecular vibrational structure from the first principles. The
computation of vibrational energy levels is extremely important not only for aiding inexperimentalists to interpret vibrational spectra, but also for understanding thethermodynamics and chemical reactions. We have developed an efficient generator of
the molecular potential energy surface (PES) and a solver of the vibrational Schrödinger
equation. The developed method is applied to biological molecules with more than 100
degrees of freedom. The usefulness of theory is discussed with a focus on a complex
vibrational spectrum of hydrogen bonded systems.
II. Methods
The PES is generated on-the-fly using an electronic structure program in a fully
automated way. The method initially generates a quartic force field (QFF) by a finite
differentiation of Hessian matrices using a low-level, electronic structure method. Then,the QFF coefficients are employed to evaluate the strength of mode coupling terms [1],and those that are found to be important are improved by replacing the QFF by a moreaccurate function based on a high-level, electronic structure theory. This scheme
exploits a multiresolution technique [2] for combining different types of functions andelectronic structure methods in a single PES. The implementation makes use of a
massively parallel architecture, in which the electronic structure calculations for eachgrid point are distributed among different nodes.
Vibrational quasi-degenerate perturbation theory (VQDPT) [3] is developed basedon a vibrational self-consistent field reference for the ground state (zero point). The
method incorporates a strong vibrational resonance by the configuration interaction (CI)and the remaining weak interactions by the perturbation theory. VQDPT is faster than aconventional CI more than 100 times without a loss of accuracy.
III. Applications
The developed methods mentioned above are applied to a series of biologically
relevant molecules: nucleic acid bases and base pairs, guanosine, their cluster withwaters, and polypeptides.
[1] P. Seidler, T. Kaga, K. Yagi, O. Christiansen, and K. Hirao, CPL 483, 138 (2009).
[2] K. Yagi, S. Hirata, and K. Hirao, TCA 118, 681 (2007).
[3] K. Yagi, S. Hirata, and K. Hirao, PCCP 10, 1781 (2008).

243

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Towards quantum chemistry on quantum computers
Jiřı́ Pittner, Libor Veis,
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech
Republic, Prague, Czech Republic
Quantum computers have a potential to change the way quantum chemistry is done.
For example, they are able to eﬃciently ﬁnd the exact solution of many-body Hamiltonian
eigenvalue problem [1]. As was shown in the seminal work by Aspuru-Guzik et. al. [2],quantum computers, if available, would be able to perform the full conﬁguration interaction (FCI) energy calculations with only a polynomial scaling, in contrast to conventional
computers where FCI scales exponentially. Of course, experimental realization of large
enough quantum computers is an extremely diﬃcult task. However, ﬁrst step towards thisgoal, calculation of H2 in a minimal basis on a real quantum computer, has been reported
recently by Lanyon et al. [3]This lecture will summarize our work in the ﬁeld of interconnection of quantum chemistry and quantum computing [4]. Improved version of the quantum full conﬁgurationinteraction (QFCI) method, which uses the iterative phase estimation algorithm and its
application to non-relativistic as well as relativistic conﬁguration interaction (CI) energy
calculations will be presented.
As far as non-relativistic CI calculations are concerned, simulations (on a conventional
computer) of QFCI calculations of the four lowest lying electronic states of methylene
molecule (CH2 ), which exhibit a multireference character were performed [4]. It has beenshown that with a suitably chosen initial state of the quantum register, one is able toachieve the probability ampliﬁcation regime of the iterative phase estimation even fornearly dissociated molecule. Concerning the relativistic calculations, we have performed
simulations of the quantum computing analogue of the Kramers-restricted CI calculations
for the SbH molecule. A minimalistic example of a quantum circuit performing sucha calculation, which might become experimentally realizable in the near future, will bepresented. Last but not least, possible use of genetic algorithms in the design of quantum
circuits for QFCI calculations will be discussed.

References[1] D. S. Abrams and S. Lloyd, Phys.Rev.Lett. 83, 5162 (1999).
[2] A. Aspuru-Guzik, A. D. Dutoi, P. J. Love, and M. Head-Gordon, Science 309, 1704
(2005).
[3] B. P. Lanyon, J. D. Whitﬁeld, G. G. Gillett, M. E. Goggin, M. P. Almeida, I. Kassal,
J. D. Biamonte, M. Mohseni, B. J. Powell, M. Barbieri, A. Aspuru-Guzik, and A. G.
White, Nature Chemistry 2, 106 (2010).
[4] J. Pittner and L. Veis, J. Chem. Phys. 133, 194106 (2010).

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Advances in Multireference Coupled Cluster Theory
Wesley D. Allen
Department of Chemistry and Center for Computational Chemistry,
University of Georgia, Athens, Georgia 30602 USA
A state-specific and rigorously size-extensive multireference coupled cluster theory(Mk-MRCC) and a companion second-order perturbation theory (Mk-MRPT2) have beendeveloped into powerful and practical tools for chemical research. The effectiveness of our
Mk-MRCC methods is established by extensive computations on benchmark systems,
including the low-lying electronic states of O2, CH2, HCF, and H2CO, the dissociation of
F2, and the problematic ozone molecule. In chemical applications of Mk-MRCC theory,
outstanding results have been obtained for the optimum geometric structures, vibrationalfrequencies, and electronic excitation energies of the organic diradicals ortho-, meta-, andpara-benzyne, as well as the cyclic polyenes cyclobutadiene and cyclooctatetraene. A
rigorous Mk-MRCC torsional surface has been generated for the classic problem of thestereomutation of cyclopropane. The seemingly simple organic molecule cyclobutanetetraone (C4O4) is demonstrated by Mk-MRCC theory to actually have a triplet rather thana closed-shell singlet ground state! Finally, joint theoretical and experimental work ispresented on novel hydroxycarbenes (RCOH; R = H, CH3, and phenyl) that has led to thefirst isolation and identification of these species.

These hydroxycarbenes show rapid

tunneling (t1/2  2 hrs) at 11 K through prodigious energy barriers of almost 30 kcal mol–1,
a remarkable phenomenon confirmed by our high-accuracy computations of barrier
penetration integrals.

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Advanced multireference quantum chemistry with large active space
Takeshi Yanai,1 Yuki Kurashige,1 Wataru Mizukami1
1
Institute for Molecular Science, Japan
We will present our recent progress in the development of efficient multireference
approaches based on the density matrix renormalization group (DMRG) method and its
partner dynamical correlation models. Following Chan’s successful adaptation of the
DMRG algorithm to ab initio quantum chemistry calculations, we use it to describe asubstantial amount of static correlation accurately with large active space formultireference calculations, e.g. CAS(28e,32o) or even larger. Developing our efficient
implementation of the DMRG method, we recently demonstrated its significant
applicability to challenging multireference chemistry, involving strongly-correlated
electronic states of transition metal complexes and π-conjugated molecules. For thelatter, we will show some novel findings in spin structures of polycarbenes (orgnaic
magntic molecules) and graphene-nanoribbons (future organic semiconductors). Theseelectronic structures associated with complex multireference electron correlation arethought to be a key to understand interesting quantum phenomena arising in organic
materials and biomolecules.
Dynamic correlation needs be taken into account to deliver a quantitative accuracy
in calculations, and is regarded as weak correlation that should be handled
perturbatively in light of efficiency. We have developed a joint theory of the DMRG
method and a canonical transformation (CT) idea to calculate the dynamic correlation
on top of multireference description with large active space. Our CT theory constructs arenormalization structure of the high-level dynamic electron correlation in an effective
Hamiltonian where the bare Hamiltonian is transformed by the unitary exponential
correlation operator. As an alternative efficient routine to approach the dynamicalcorrelation problems, we have recently developed a novel extension of DMRG which
has led to its combination with the CASPT2 method. We will discuss some theoreticalaspects of the DMRG-CT and DMRG-CASPT2 theory and their applications toquasi-degenerate electronic states in chemistry.
[1] D. Ghosh, J. Hachmann, T. Yanai and G. K-L. Chan, J. Chem. Phys. 128, 144117 (2008).
[2] Y. Kurashige and T. Yanai, J. Chem. Phys. 130, 234114 (2009).
[3] T. Yanai, Y. Kurashige, E. Neuscamman, G. K-L. Chan, J. Chem. Phys. 132, 024105(2010).
[4] E. Neuscamman, T. Yanai, G. K-L. Chan, Int. Rev. in Phys. Chem. 29, 231-271 (2010).
[5] W. Mizukami, Y. Kurashige, and T. Yanai, J. Chem. Phys. 133, 091101 (2010).

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Study of Simulation Method of Time Evolution in Rigged QED
Kazuhide Ichikawa,1 Masahiro Fukuda,1 Akitomo Tachibana1
1
Department of Micro Engineering, Kyoto University, Kyoto 606-8501, Japan
We discuss how we can formulate time evolution of physical quantities in theframework of the Rigged QED (Quantum ElectroDynamics) [1]. The Rigged QED
is a theory which has been proposed to treat dynamics of charged particles andphotons in molecular systems in a quantum ﬁeld theoretic way. In addition to theordinary QED which is Lorentz invariant with Dirac (electron) ﬁeld and U(1) gauge(photon) ﬁeld, Schrödinger ﬁelds which represent nuclei are added. In this way,
dynamics of nuclei and their interaction with photons can be treated in a uniﬁed
manner. To solve the dynamics in the Rigged QED, we need diﬀerent techniquesfrom those developed for the conventional QED. As a ﬁrst step toward this issue, we
propose a procedure to expand the Dirac ﬁeld operator, which represents electrons,
by solutions of the Dirac equation for electrons in nuclear potential [2] and derive
time evolution equations for the creation and annihilation operators.
 D 
We expand Dirac ﬁeld operator as ψ̂(ct, r) = N
r). Here,
a=± êna (t)ψna (n=1
ψna (r) is a normalized orbital obtained by solving the Dirac equation, n is a label
for the orbital whose superscript a denotes electron (positron) orbital when +(−).
ên+ is the electron annihilation operator and ên− is the positron creation operator.
The Dirac ﬁeld equation can be expressed as ih̄γ μ D̂eμ (x)ψ̂(x) = me cψ̂(x) with thegauge covariant derivative D̂eμ (x) = ∂μ + i Zh̄ce e Âμ (x), Ze = −1 where Âμ (x) is thegauge ﬁeld operator. We derive time evolution equation for the annihilation/creation
operator from this equation. (At this stage, we adopt the adiabatic approximation
for the nuclear motion, namely neglecting “the Rigged current”, for simplicity.)
We also discuss how time evolution of physical quantities can be calculated using
this equation. In particular, we discuss “local refractive index”, which may provide
a new viewpoint for molecular chirality, can be deﬁned by the time evolution ofpolarization and magnetization operators.
[1] A. Tachibana, J. Chem. Phys. 115, 3497 (2001); J. Mol. Struct. (THEOCHEM),
943, 138 (2010).
[2] W. H. Furry, Phys. Rev. 81, 115 (1951); “Relativistic Quantum Theory PartII”, E. M. Lifshitz and L. P. Pitaevskii, Pergamon Press (1974).

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8C2-2I

Analytical Principles and the Evolution of Physical Laws
Erkki J. Brändas
Department of Physical and Analytical Chemistry, Quantum Chemistry
Uppsala University, Sweden

Abstract
In preceding accounts [1,2] we have advanced a retarded-advanced sub-dynamics
transcending standard probabilistic formulations providing a wide-range of interpretations. The contradiction between time reversible microscopic physical laws and the irreversible nature of thermodynamical equations are examined from this standpoint. The
subjective nature of statistical mechanics in connection with a theoretical formulation
relative to a given level of description, is also re-examined. A complex symmetricansatz, incorporating both time reversible and time irreversible evolutions discloses theevolution of the basic laws of nature and reveals new orders of organization. Examples
are given from the self-organizational behaviour of complex biological systems as wellas background dependent relativistic structures including Einstein’s laws of relativity,
the time delay, the gravitational redshift and the perihelion movement of Mercury. A
promising solution to the present conundrum is provided by a specific informity rule incombination with a Gödelian like rule of decoherence code protection. The theory gives
an interesting cosmological scenario in absolute agreement with the second law.
[1] E. Brändas, Mol. Phys. 108, 215 (2010).
[2] E. Brändas, Int. J. Quant. Chem. 111, 215 (2011).

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