Vitali Antonovich Tolkachev is an outstanding scientist in the field of molecular spectroscopy and quantum electronics; Professor, Doctor of Physics and Mathematics; Academician of the National Academy of Sciences of Belarus.
V.A. Tolkachev was the associate editor of the journal "Zhurnal Prikladnoi Spektroskopii" from 1994.
Vitali Tolkachev, Belarusian, was born on June 28, 1934 in the Minsk region, village Skirmontovo.
In 1952, upon graduating Dovsk Secondary School (Rogachev district, Gomel region, Belarus),Vitali Tolkachev has enrolled in the V. I. Lenin Belarusian State University and graduated with distinction from it in 1957. The State appointments board has assigned V. Tolkachev to laboratory of professor Borisevich N. A. (Institute of Physics and Mathematics, Academy of Sciences of BSSR, Minsk, 1957—1958), where under the guidance of prof. Borisevich, he completed a post-graduate course (1960—1962) and defended a Ph.D. thesis titled “Statistical mechanism in absorption and fluorescence of vapours of complex molecules” (1964). A subsequent scientific activity has been generalized in Dr. Sc. dissertation “Energetics of free complex molecules in their spectral, luminescent and laser behaviors” (1980).
The main data of his scientific and social scientific activities are as follows:
corresponding member of the Acad. of Sci. of BSSR-Belarus (1984—2000), head of laboratory (1984—2007), professor (1990); deputy director of Scientific-Technical Center of Goznak of Belarus (1992—1996), Vice-President of Belarussian Physical Society (1999—2005), deputy director of Physics, Mathematics, and Informatics Department of National Academy of Sciences of Belarus (2003—2007), member of National Academy of Sciences of Belarus (2000— ).
The area of his personal scientific interests lies mainly in molecular spectroscopy and (starting from 1964) in molecular quantum electronics. In particular, he found 10 new laser lines in pulsed inert-gas lasers, and from 1965 became engaged in liquid, polymer, and vapor dye lasers. In 1965, V. Tolkachev and N. Borisevich formulated main conditions governing the lasing ability of complex molecules. They were the first to invent a vapor-phase dye laser, which brought V. Tolkachev closer to physics of complex polyatomic molecules in the vapor state. Dozens of dyes capable of lasing have been found and dye-based active/passive laser elements and dye-doped/dye-draft polymers developed by him.
He studied energy selectivity of optical transitions in gas-phase complex molecules and developed methods to measure characteristics of the selectivity. From then on, his scientific interests were for the most part centered on rotational anisotropy of gas-phase complex molecules, mechanisms of anisotropy formations, and its spectral manifestations, particularly in polarized luminescence. He and his colleagues discovered optically and electron-beam induced anisotropy of complex molecule vapors and he explained a mechanism for polarization of e-beam-induced fluorescence in these vapors. He studied mechanisms of fluorescence depolarization by nonrigidity or through encounters of molecules in the gas-phase, showed a possibility to obtain in such a way gas-kinetic cross-sections even for non-luminescent molecules, and offered a simple method to determine a probability of quenching the electron-excited state of gas-phase complex molecules by oxygen in a single collision.
V. A. Tolkachev revealed rather simple nature of rotational quantum echo dynamical mechanism in asymmetric top molecule vapors. This gave straightforward formulas to connect the echo period with rotational constants of molecular tops. He showed that the quantum echo may be observed both in multipole optical transitions and in optical activity.
For the development of a new scientific trend "Spectroscopy of free complex molecules", V. A. Tolkachev and co-authors, N. A. Borisevich, B. S. Neporent, and V. V. Gruzinskii, were awarded the Lenin Prize (1980). His achievements in studying the spectral manifestations of rotational dynamics of electronically excited polyatomic molecules were honored with the State Prize of Belarus (1998).