Vadim F. Bratsev
(24.02.1932 - 27.06.2006)

Vadim Fedorovich Bratsev was born on February 24, 1932 in Leningrad, Petrogradsky district in a family of intellectuals. His father, Fyodor Pavlovich, worked as an engineer at a factory in the Moscow district. His mother, Valentina Konstantinova, was both the director of the school for working youth at this factory and the teacher of Russian and literature. Vadim was gifted child and as a boy he learned to play violin. In 1940, he entered school, but soon came the war. Both his father's factory and his mother's school were evacuated to Novosibirsk, and Vadim went there with his parents. In 1945 he returned to Leningrad with his parents and continued his education at school No 374 of the Moskovsky district. Life after the war was not easy, the more so that Bratsev family lost the apartment they lived in before the war and occupied now two rooms in a communal apartment granted by Vadim father's factory. In spite of all difficulties Vadim education at school was successful and after graduating from the school in 1950, he entered the Department of Mathematics and Mechanics of Leningrad State University. At the University he attended lectures of prominent Professors G.M. Fikhtengol'ts, S.L. Sobolev, L.V. Kantorovich, D.C. Faddeev, M.K. Gavurin. His graduating thesis was made under the supervision of Mark Konstantinovich Gavurin, one of the founders of linear programming.

In 1955, after the graduation from the University, Vadim Fedorovich was enlisted as junior researcher at the Department of Theoretical Physics of the Leningrad State University Physics Department. The Theoretical Physics Department was headed by the Academician V.A. Fock. The Vadim Fedorovich enlisting was initiated by Professor G.F. Drukarev, who was looking for a bright mathematician, expert in numerical methods. The development of the quantum-mechanical methods of the electronic structure calculations for atoms and molecules was one of the most important projects of Theoretical Physics Department. Professor M.G. Veselov, the Department Deputy Chief, suggested to Vadim Fedorovich to take part in the Hartree-Fock method application to real systems, as HF method was at that time one of the most advanced theoretical methods of the electronic structure calculations.

That was the time when the practical use of computers just started. Almost immediately it became clear that the electronic structure calculations of real systems are so massive that without this new technology they cannot be performed. Because of this reason, in 1960 a special scientific group was organized in the Leningrad Branch of the Mathematical Institute of the Russian Academy of Sciences (LOMI) by its director Professor G.I. Petrashen. Vadim Fedorovich was invited there to work as a researcher. When moving to LOMI Vadim Fedorovich still kept close relations with the university theoretical department and its members. By that time his first scientific results on the atomic electronic structure began to appear.

First it was the analytical wave functions of atoms and ions calculations. Based on results of these calculations several papers were published in 1961-1963 by Vadim Fedorovich with M.G. Veselov and other co-authors. However the electronic structure calculation was not the only problem Vadim Fedorovich was interested in. So in 1962 the well known work "An integral representation of the Green function of the energy operator for a particle in a Coulomb field" was completed together with E.D. Trifonov. The impetus for this work was the famous paper by V.A. Fock on the four-dimensional symmetry of the hydrogen atom. In 1963 Vadim Fedorovich together with I.V. Abarenkov published the paper "Effective potential method in the theory of atoms", which formed the basis of the model pseudopotential theory. It should also be mentioned a series of pioneering works of V.F. Bratsev and V.I. Ochkur (1965) on the exchange excitation of helium atom by electron impact, in which the exchange scattering has been correctly accounted for in the first Born approximation. However, the real recognition of Vadim Fedorovich scientific achievements came to him after the publication in 1965 the paper "The energy of the ground state of the molecule in the adiabatic approximation". In this paper he proved that the adiabatic approximation, contrary to the variational principle, provides an approximation to the exact total energy from below. Now this result is known as the theorem named after him (in the foreign literature the term Brattsev-Epstein theorem is used).

Nevertheless, his main goal in this period was to develop the universal program for the numerical solution of the Hartree-Fock equations for light atoms, and by the mid-1963 this program was completed. It was one of the first in the world and the first in the USSR numerical realization of the Hartree-Fock method for atoms. It formed the basis for V.F. Bratsev Ph.D. thesis, which he successfully defended in 1964 at Vilnius State University. One of his official opponents was Academician Lit.SSR Adolfas Pranovich Yutsis, whose estimation of Vadim Fedorovich work was very high. Later, the results of these calculations were collected in the book "Tables of atomic wave functions," published in 1966. Vadim Fedorovich permanently refined and updated the program in order to employ the full capacity of modern computers and continued the atomic wave functions calculations. In result, he published in 1971 significantly expanded "Tables of atomic wave functions." Some time later he developed the program for atoms and molecules electronic structure calculations with the configuration interaction included and worked out the numerical realization of the relativistic Hartree-Fock-Dirac method (1977). Vadim Fedorovich students G.B. Deineka, I.I. Tupitsyn and others actively participated in these studies. The obtained wave functions were used for a number of physical applications: calculations of atomic polarizabilities, an electron--atomic collision cross sections, the transition frequencies, the oscillator strengths, spectroscopic moments and magnetic susceptibilities, etc.

In 1966 Vadim Fedorovich was listed as the senior researcher and later (1969) he was promoted to the associate professor position at the Quantum Chemistry Department of the Leningrad State University Chemistry Department. The Quantum Chemistry Department was founded due to initiative of Academician V.A. Fock and Professor M.G. Veselov. Computers contributed significantly to the progress in the field of theoretical chemistry, in particular, because they offer the possibility for numerical simulation of molecules and processes in them. Vadim Fedorovich became closely involved in solving problems of multicenter quantum chemistry and solid state physics. Of particular importance are the method to describe the effective state of an atom in a molecule, developed by him jointly with Yu.G. Khait and A.V. Tulub and empirical method of ions in metal oxides polarizability calculations developed in collaboration with I.V. Abarenkov and A.V. Tulub.

Scientific interests of Vadim Fedorovich were very broad and were not limited to the quantum chemistry. It is worth mention the series of his work in statistical physics, addressing the high-temperature expansions in the Ising model with arbitrary magnetization (with N.M. Bogolyubov and A.N. Vasiliev) and some variants for chain of Bogolyubov equations uncoupling. V.F. Bratsev works on quantum mechanics and plasma physics are also well known. One of his latest interests was the holography theory.

It should be stressed the outstanding pedagogical skill of Vadim Fedorovich. During over than 45 years of teaching, he gave lectures and seminars on quantum mechanics, quantum chemistry, theory of atomic structure, mathematics, programming languages. He developed the original lecture course "Computers in Chemistry". His wide experience and deep understanding are expressed in books "Methods for calculating the electronic structure of atoms and molecules" (1976, with V. I. Baranovsky, A. I. Panin, V.M. Tretiak) and "Principles of Quantum Chemistry" (1989, with I. V. Abarenkov and A.V. Tulub). The latter is one of the best textbooks in the field of quantum mechanics of atoms and molecules in Russia.

Vadim Fedorovich was very demanding to himself and to his students. At the same time in ordinary life he was very sympathetic person, always willing to help and to share his knowledge and experience. His friendship intellectually enriched every person, and often helped in difficult moments of life. His kindness was unlimited. It seemed that he just can’t get angry. He was also surprisingly modest.

Vadim Fedorovich will forever remain in the memory of friends, relatives, colleagues and students.