Abstracts of the TCTC 2014

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[1] Popelier, P. L. A.; Brémond, É. A. G. Int.J.Quant.Chem. 2009, 109, 2542.

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High accuracy methods /Relativistic corrections

Debashis Mukherjee

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Seiichiro Ten-no

Department of Computational Science, Graduate School of System Informatics, Kobe University

Recent advances in explicitly correlated electronic structure theory

In quantum chemistry, one of the main obstacles to accurate electronic structure calculations is the slow convergence of a CI expansion. F12 theory exploiting geminal basis functions with the Slater correlation factor leads to greatly improved convergence of correlation energies. Recent developments based on the rational generator approach from the cusp conditions is summarized. Four-component relativistic treatment and massively parallel implementation of F12 methods will be also presented.


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Tron Saue

Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3 (Paul Sabatier), 118 route de Narbonne, 31062 Toulouse, France

Parity violation in chiral molecules

The parity violation associated with the weak force implies that left- and right-hand forms of chiral molecules are diastereomers rather than enantiomers. A predominantly French collaboration of theoreticians and experimentalists, physicists and chemists, hunt for the signature of parity violation in the vibrational spectra of chiral molecules. The task of theory, using relativistic molecular quantum chemistry, is to guide experiment in the search for suitable candidate molecule.

Trond.png


In this talk I review recent progress with particular emphasis on the analysis and understanding of the mechanism of parity violation in molecules. A successful experiment will have a significant impact on our understanding of the stability and dynamics of chiral molecules as well as the origin of biochirality.

[1] Radovan Bast, Anton Koers, André Severo Pereira Gomes, Miroslav Ilia², Lucas Visscher, Peter Schwerdtfeger and Trond Saue, Analysis of parity violation in chiral molecules, Phys. Chem. Chem. Phys. 13 (2011) 854

[2] Benoit Darquié, Clara Stoeffer, Alexander Shelkovnikov, Christophe Daussy, Anne Amy-Klein, Christian Chardonnet, Samia Zrig, Laure Guy, Jeanne Crassous, Pascale Soulard, Pierre Asselin, Thérèse R. Huet, Peter Schwerdtfeger, Radovan Bast and Trond Saue, Progress toward the first observation of parity violation in chiral molecules by high-resolution laser spectroscopy, Chirality 22 (2010) 870

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Toru Shiozaki

Department of Chemistry, Northwestern University

Modern Multireference Electron Correlation Methods

In this lecture, I will present the state of the art of multireference electron correlation theories for strongly correlated systems. The standard quantum chemistry methods, such as density functional theories and single-reference coupled-cluster theories, break down when wave functions are not approximated well by a single Slater determinant. Such situation includes (1) electronic structures of transition metal complexes that are important for catalytic reactions; (2) two-electron excited states that play a central role in next-generation solar energy conversion; and (3) state-crossing between the ground and excited states, relevant to photo-switches. First, I will describe the so-called completely active space self-consistent field (CASSCF) method that is a multi-determinant extension of the Hartree–Fock method. I will also discuss various approximate variants of CASSCF, including our recent development of an active space decomposition strategy and its connection to density matrix renormalization group. Second, I will present conventional electron correlation models that are based on multi-determinant reference states, such as second-order perturbation (CASPT2), configuration interaction (MRCI), and so on. Finally, I will present new approaches in this field, such as integration with explicit correlation methods, multireference coupled cluster methods, and beyond.

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Density functional theory

Guanhua Chen

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John Perdew

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Adrienn Ruzsinszky

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Xin Xu

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Weitao Yang

Duke University, USA

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Thomas Frauenheim

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Mario Piris

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Frontiers in computation

Robert Harrison and W. Scott Thornton

Institute for Advanced Computational Science, Stony Brook University

Evaluation of the GW method for applications in chemistry


The GW method is one of a hierarchy of many-body methods that forms an analogue in the theory of solid-state-systems to coupled-cluster family of methods,though it is of necessity based upon the Green’s function rather than the wave function. We examine the formulation and implementation of the GW and relatedmethods and evaluate their performance in comparison to standard quantum chemical approaches.


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Roland Lindh

Uppsala University

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Peter Taylor

University of Melbourne, Australia

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Kazuo Kitaura

Kobe University, Kobe Japan

The Fragment Molecular Orbital Method and Its Applications to Very Large Molecules

The fragment molecular orbital (FMO) method[1] is an approximate ab initio MO computational method for vary large molecules such as proteins. In the method a molecule is divided into fragments and ab initio MO calculations are performed on the fragments, their dimers and optionally trimers to obtain the total energy and other properties of the whole molecule. The method reproduces regular ab initio properties with good accuracy. Various FMO-based correlation methods have been developed including density functional theory (DFT), 2nd order Møller-Plesset perturbation theory (MP2), coupled cluster theory (CC), and MCSCF. Polarizable continuum model (PCM) was interfaced with FMO, allowing one to treat solvent effects of real size proteins. Recently, the analytical energy gradients and the second derivatives have been developed. In this presentation, I will talk about the FMO method and its applications to biomolecules.

[1] “The Fragment Molecular Orbital Method: Practical Applications to Large Molecular Systems”, Dmitri.G..Fedorov, Kazuo Kitaura, Eds., CRC press, Boca Raton, 2009.

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Takahito Nakajima

RIKEN Advanced Institute for Computational Science, Kobe, Japan

NTChem Program Package

An atomic- and molecular-level understanding of drug actions and the mechanisms of a variety of chemical reactions will provide insight for developing new drugs and materials. Although a number of diverse experimental methods have been developed, it still remains difficult to investigate the state of complex molecules and to follow chemical reactions in detail. Therefore, a theoretical molecular science that can predict the properties and functions of matter at the atomic and molecular levels by means of molecular theoretical calculations is keenly awaited as a replacement for experiment. Theoretical molecular science has recently made great strides due to progress in molecular theory and computer development. However, it is still unsatisfactory for practical applications. Consequently, our main goal is to realize an updated theoretical molecular science by developing a molecular theory and calculation methods to handle large complex molecules with high precision under a variety of conditions. To achieve our aim, we have so far developed several methods of calculation. Examples include a way for resolving a significant problem facing conventional methods of calculation, in which the calculation volume increases dramatically when dealing with larger molecules; a way for improving the precision of calculations in molecular simulations; and a way for high-precision calculation of the properties of molecules containing heavy atoms such as metal atoms. We have integrated these calculation methods into a software package named NTChem that we are developing, which can run on the K computer and which contains a variety of high-performance calculation methods and functions. By selecting and combining appropriate methods, researchers can perform calculations suitable for their purpose. For example, it is possible to obtain a rough prediction of the properties of a molecule in a short period of time, or obtain a precise prediction by selecting a longer simulation. In addition, NTChem is designed for high performance on a computer with many compute nodes (high concurrency), and so it makes optimum use of the K computer’s processing power. In this talk, I will introduce the current and future projects for the NTChem software.


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Reducing complexity

Garnet Chan

Princeton University, USA

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Thomas Miller

Caltech, USA

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Dominika Zgid

University of Michigan, USA

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Gustavo Scuseria

Rice University, USA

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George Booth

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Theoretical spectroscopy / Magnetism

Jeppe Olsen

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Daniel Crawford

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Trygve Helgaker

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Dynamics

Florent Calvo

University of Lyon, France

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Fabien Gatti

Université de Montpelier 2, France

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Aaron Kelly

Stanford University, USA

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Benjamin Lasorne

Imeperial College, UK

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Troy Van Voorhis

Massachusetts Institute of Technology

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Computational biochemistry / Solvation

Aurelien de la Lande

Paris-Sud University, France

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Lars Pettersson

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Ursula Roethlisberger

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G. Andres Cisneros

Department of Chemistry, Wayne State University, Detroit, MI 48202, USA

Development of accurate force fields for classical simulations

We have developed a novel force field, called the Gaussian Electrostatic Model (GEM), that employs explicit molecular charge densities. These densities are employed to calculate each term in the Morokuma-style decompositon of the quantum mechanical intermolecular interaction, i.e., Coulomb, exchange-repulsion, polarization, charge-transfer and dispersion. GEM enables the evaluation of intermolecular interactions for molecular systems with errors below chemical accuracy for each component, and provides a novel procedure to obtain distributed multipoles (GEM-DM). We will discuss the details of our method, advances in the implementation of a GEM variant for molecular dynamics simulations, recent applications of this variant for liquid water simulations, and applications of GEM-DM for the development of AMOEBA for ionic liquids simulations.


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Yingkai Zhang

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Guillaume Lamoureux

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Material science/ Catalysis

Michel A. Van Hove

Institute of Computational and Theoretical Studies & Department of Physics, Hong Kong Baptist University, Hong Kong SAR, China

Rotor molecules as machines

Molecular machines are gaining increasing interest, especially from a biological perspective. They promise to create and control mechanical motion at length scales down to the nanometer. Some molecular machines cause reciprocal motion, as in muscles and switches, while others cause rotational motion, as in flagellae: we focus here on rotor molecules.

Nature developed a variety of molecular machines to create and control motion. These natural machines tend to be complex and robust, due to the need to operate reliably for long times in variable biological environments.

In the last few decades, scientists have synthesized a wide range of new, relatively simpler molecular machines and learned to control and observe some of their important motions, mostly in solution. Increasingly, molecular motors have also been investigated at solid surfaces, allowing the use of surface science techniques for studying monolayers of well-oriented molecules. Nanoscience techniques have added further possibilities.

We shall discuss basic issues of the operation of molecular motors, including energy conversion steps, continuous energy supply, the role of thermal energy, intentional start and stop of motion, and unidirectionality of motion. Without intentional control of these aspects, motors create random motion and are largely useless.


This work was supported by grants from the Hong Kong Baptist University Strategic Development Fund, the Hong Kong RGC, the NBRPC and the NSFC, and by HKBU’s High Performance Cluster Computing Centre, which receives funding from the Hong Kong RGC, UGC and HKBU.

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RuiQin Zhang

CiteU HongKong

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Alexis Markovits

Université Pierre et Marie Curie

Strong Metal Support Interaction: an electron count

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Metal/Metal-oxide interface is an attractive topic in many aspects. It has been given considerable attention due to the various technological applications for electronic or photovoltaic devices, coating or sensor devices. The domain we are interested in is heterogeneous catalysis where the very special interaction between a support and a metal aggregate is known as Strong Metal Support Interaction (SMSI). The activation of the so-called SMSI catalyst is indispensable. Several explanations have been proposed since the discovery of SMSI as for instance metal dispersion allowing the formation of metal nanoparticules of various sizes and morphologies. Another explanation is the electronic effect. In this talk, we will mainly be focusing on this aspect. We take as an example CO dissociation that is important in many catalytic reactions. The first point is to evaluate and to rationalize the interaction strength between the metal M (M=K-Zn) and the reducible support TiO2. Then, CO dissociation on supported M is considered: is it assisted by hydrogenation? The influence of surface oxygen vacancy will be evaluated. The case of Iron supported on TiC support is developed: what is the influence of the support on CO dissociation? CO reactivity on bare and supported Fe clusters is compared.

Electron count and orbital analysis for understanding catalysts are supported by periodic DFT calculations. ↑ top of this page

Monica Calatayud

Univesité Pierre et Marie Curie

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Javier Fdez. Sanz

Universidad de Sevilla, Spain

Mechanism of the Water-Gas Shift Reaction: Insights from First Principles Calculations

The traditional approach to the optimization of metal/oxide catalysts has focused on the properties of the metal and the selection of the proper oxide for its dispersion. The importance of metal–oxide interfaces has long been recognized, but the molecular determination of their properties and role is only now emerging. In this talk we focus on the water gas shift reaction, WGSR, a chemical process that allows for obtaining clean molecular hydrogen: CO+H2O → CO2+H2. Bulk like phases or extended surfaces of coinage metals show low catalytic activity that improves when supported on a metal-oxide. Several reaction mechanisms have been proposed. In the redox mechanism, CO reacts with oxygen derived from the dissociation of H2O. In the associative process, the formation of a carboxyl intermediate must precede the production of H2 and CO2. The mechanism involves several steps that can take place at different sites of the catalyst: the metal, the support or the interface. Besides the dispersion effect, the role of the support is to increase the interaction with water and facilitate its dissociation. DF calculations show that supported CeOX nanoparticles are highly efficient in water splitting. Furthermore The M/CeOx /TiO2 (110) surfaces display outstanding activity for the WGS, in the sequence: Pt > Cu > Au. Such a high catalytic activity reflects the unique properties of the mixed-metal oxide at the nanometer level. STM and DF calculations show that Ce deposition on TiO2 (110) at low coverage gives rise to Ce2O3 dimers specifically aligned, indicating that the substrate imposes on the ceria NPs unusual coordination modes enhancing their chemical reactivity.

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Frederik Tielens

Univesité Pierre et Marie Curie

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Chemical concepts

Paul Ayers

Using molecular properties to define similarity measures and predict chemical properties


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Jerzy Cioslowski

Institute of Physics, University of Szczecin, Poland

A tale of natural orbitals

Natural orbitals (NOs) and their occupancies constitute a convenient and conceptually appealing representation of the one-electron reduced density matrix from which all one-electron properties (including the majority of indices of interest to chemists) follow. However, their importance notwithstanding, properties of NOs are not fully understood. In particular, the existence of NOs with vanishing occupancies has been the subject of several recent studies with contradictory conclusions.

In this talk, after a brief introduction to properties of natural orbitals and their occupancies, we discuss results of our recent work uncovering the existence of solitonic NOs that resolves the apparent contradictions encountered in the previously published research. Both numerical calculations and analytical derivations are presented.


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Robert Ponec

"New theoretical methods for the analysis of chemical bonding


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Patrick Bultinck

Degenerate states: a challenge to common reactivity descriptors


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Angel M Pendas

Learning (and teaching) chemical bonding from the statistics of electron populations in spatial domains


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Paul Geerlings

Conceptual DFT, Theoretical Models of Chemical Bonding


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Eduard Matito

Aromaticity


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Posters

Alexey I. Baranov

Inorganic Chemistry II, Department of Chemistry and Food Chemistry, Dresden University of Technology, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany.

Indicators for Quantitative Atomic Shell Structure Analysis from Fully Relativistic Calculations

One of the most fundamental concepts of chemistry is the concept of atomic shell structure. In the field of real space bonding analysis several bonding indicators have been proposed to reveal shell structure of chemical elements and thus visually represent key entities of chemical bonding like bonds or lone pairs. This type of analysis should be especially beneficial for relativistic 2c- or 4c-formalisms, eliminating the necessity of direct analysis of complicated multicomponent wavefunction.

This work presents an electron localizability indicator for spatially antisymmetrized electrons, which can be used to reveal an atomic shell structure at quantitative level in real space from the results of fully relativistic calculations. The indicator is universal and equally applicable for two-component and scalar-relativistic methods. Shell structures of heavy elements, calculated using this indicator from the results of fully relativistic, ZORA scalar relativistic and nonrelativistic numerical Kohn-Sham LDA calculations are reported and compared with each other.

[1] Baranov, A. I. J. Comp. Chem. 2014, 35, 565.

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Contributor's name

Affiliation

Title

Summary


[1] Popelier, P. L. A.; Brémond, É. A. G. Int.J.Quant.Chem. 2009, 109, 2542.

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