#### Robert A. Evarestov

Doctor of physico-mathematical sciences, professor, head of department

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#### Research areas

- Structure and stability of nano-systems: carbon and inorganic nanotubes, fullerenes, surfaces

#### Andrey I. Panin

Ph.D

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#### Research areas

- Mathematical Chemistry: the study of electron Fock space and various algebraic structures on this space

#### History of the Quantum Chemistry Department

The practical steps to realize this decision were undertaken by the Dean of the Chemical Department A. N. Murin and the Director of the Scientific Institute of Chemistry A. G. Morachevskiy with the help of the Physical Department professor, major specialist in quantum mechanics M. G. Veselov. The result of these efforts was the establishment of the Quantum Chemistry Division in 1967-1968. The Physical Department associate professor A. V. Tulub was invited to be a Head of the Division.

The original staff of the Division consists of chemist V. I. Baranovskiy, mathematicion V. F. Bratsev and theorists in physics N. P. Borisova and R. A. Evarestov. This membership of the Division was able to embrace practically all trends of modern Quantum Chemistry.

The first Head of the Division was A. V. Tulub, Doctor of Physics and Mathematics, Professor, Active member of the Russian Academy of Natural Sciences. He is author of more than 120 scientific publications on the various subjects of theoretical physics and chemistry. The sphere of the research interests of A. V. Tulub includes ab initio and semi-empirical calculations of molecular systems polarizability, theory of van der Waals interactions of molecular networks with a surface, calculations of the vibrational spectra of molecules, ab initio calculations of the metastable particles properties, application of quantum electrodynamics methods in calculations of electron density at he nucleus of the atom of heavy elements.

In present time professor Robert A. Evarestov, Doctor of Physics and Mathematics, honored worker of science of Russia, active member of the Russian Academy of Natural Sciences, foreign member of the Latvian Academy of Sciences Humboldt professor, is the head of Quantum Chemistry Division. He is widely known and esteemed specialist in quantum chemistry, author of 200 scientific publications and six monographs. R. A. Evarestov carries out research in the area of the multi-electron systems theory which have been initiated by the worldwide known Petersburg scientific school of V. A. Fock and his assistants – professors M. I. Petrashen and M. G. Veselov.

He developed a new research direction of the modern theoretical chemistry – quantum chemistry of solid. This direction is based on the application of the molecular models of the crystals and the computational methods of the theory of molecules intended to solve the problems of solid state chemistry.

The scientific approach developed in the publications of Evarestov takes as a foundation the comparative analysis of the symmetry of molecules and solids coupled with essential employment of a local symmetry of atom in a multi-atomic system.

From the beginning of his work at Quantum Chemistry Division doctor of chemistry, professor, RANS corresponding member Victor Ivanovich Baranovskii investigated the electronic structure of the transition metal complexes. Together with Dr. O. V. Sizova he found out electronic mechanism of trans-influence. These conclusions were based on the results of quantum chemical computations and the perturbation theory application.

The packages of computer programs for semi-empirical and ab initio calculations of the molecular systems properties were created under his leadership. These computer programs were unique instruments in our country at that time. Also the research works on the simple chemical reactions were initiated under his leadership.

In present time the sphere of research interests of V. I. Baranovskii includes the quantum chemistry of excited states of the complexes and the complex nanosystems which were synthesized using “ordinary” mononuclear complexes as well as those synthesized using transition metal clusters.

Ph.D. in chemistry, head of the laboratory of high-performance calculations Andrei Ivanovich Panin is one of the first graduates of the Quantum Chemistry Division (1970). The area of his research interests includes electron configuration interaction, calculations of potential energy surfaces of molecular systems, theoretical treatment of gas-phase reactions, mathematical methods of quantum chemistry. He proposed a version of the configurations interaction method including arbitrary restrictions on the occupancies of groups of MOs. The corresponding algorithms and programs were worked out. He suggested new models of the Fock space and demonstrated that the Fock space can be endowed with new multiplications essentially different from Grassmann’s and Clifford’s ones. These new multiplications turned out to be closely related to the non-linear methods of quantum chemistry and, in particular, to the CC method. Using methods of modern differential geometry, A. Panin performed a study of evolution of many electron systems on manifolds in the space of their states and demonstrated how the curvature of the surface where a system evolves is connected with the TD methods of quantum chemistry. At present A. Panin works on the problems connected to the symmetry of 1-periodic systems.

Ph.D. in chemistry, associate professor Sergey Georgievich Semenov is a graduate of the Quantum Chemistry Division, 1971. In 1973-1980 he proposed a theoretical definition of the valency. According to this definition the valency is equal to the doubled dispersion of a number of electrons belonging to an atom of a chemical compound. In 1977 he also proposed a concept of unshared electronic occupation. He worked out generalized method of self consistent field which makes it possible to take into account the known equalities including the density matrix.

A. V. Bandura, associate professor, with R. A. Evarestov works on problems in the energetic and structure of the crystalline oxides surfaces. The modern methods of quantum chemistry are used to calculate the characteristics of an electronic structure of the surfaces. The objects of their investigations are simple and complex oxides of transition and non-transition metals: TiO2, SrZrO3, SnO2, MgO and so on.

A. V. Bandura in close cooperation with Pensylvania University (USA) performs a study of the systems which are modelling water adsorption and adsorption of some ions on the surface of the above mentioned crystals. The results of the quantum chemical computations are used to elaborate pair interaction potentials which subsequently are applied for statistic-thermodynamics simulations of the oxide-solution interface systems by molecular dynamics.

#### The main research interests of the Quantum Chemistry Department

The development of the group theory methods intended to study electronic and vibrational structures of multi-atomic and complex molecules and crystals using local symmetry group. The analysis of the nature of chemical bonding in crystalline solids (transition metal oxides, high temperature superconductors, fullerenes). The investigation of vibrational properties of crystals with the help of local symmetry group method for phonon symmetry analysis.

Team leader - Doctor of Physics and Mathematics, Professor Robert A. Evarestov.

Ab initio calculations of gas-phase reactions, potential energy surfaces of ground and excited states, mathematical methods of quantum chemistry.

Team leader - Ph.D. in Chemistry, Head of the laboratory of high-performance calculations

Andrey Ivanovich Panin.