Obituary of Yury Demkov

Yury Nikolayevich Demkov, an outstanding scientist in the field of theoretical atomic physics, and one of the pioneers in the development of the theory of atomic collisions, passed away on November 15, 2010 in St. Petersburg, Russian Federation.

Yury N. Demkov was born on April 12, 1926 in Leningrad, USSR (now St. Petersburg, Russia) to a family of architects. His father designed and constructed public buildings in Leningrad. He died in Leningrad in 1941 when the city was under siege during World War II. His mother was one of the first female Russian architects; she designed buildings in many cities of the USSR. In 1941, when the battle front approached Leningrad, Yury and his mother moved to Yaroslavl and then to Kuibyshev (now Samara). In 1943, after he finished high school, Yury enrolled in the Moscow Steel Institute. In 1944, when he turned 18, he was drafted into the Red Army and took part in World War II. When the army was advancing to the West, he walked through Ukraine and Poland. After the victory, he left the army in September of 1945 and returned to Leningrad, where he was admitted to the Physics Department of the Leningrad State University. He graduated with honors in 1949. He was then offered an Assistant Professor position in the Theoretical Physics Division headed by Professor V. A. Fock. Until his death, Yury worked for Leningrad (St. Petersburg) State University. In 1954 he defended his PhD thesis, and in 1966 he received the Doctor of Science degree. Yu. N. Demkov occupied successively positions of Assistant Professor, Senior Researcher, Associate Professor, and Professor. From 1975 to 1991 he served as Head of the Quantum Mechanics Division of the Physics Department.

His most important results concerned the quantum theory of atomic collisions beginning with his diploma work on resonance charge transfer. Such terms as ‘Demkov model’, ‘Demkov-Osherov model’, ‘Rosen-Zener-Demkov model’ are well known in the theory of non-adiabatic transitions. He also studied variational principles in collision theory and wrote a monograph on them (1958, English translation 1963). Together with his former student, Professor V. N. Ostrovsky, he carried out research on zero-range potentials in atomic physics which resulted in a book (Yu. N. Demkov and V. N. Ostrovsky 1975, English translation 1988). In a series of papers, Yu. N. Demkov and V. N. Ostrovsky studied the symmetry of energy level filling in the periodic table and explained the well-known “n+l” rule. A major contribution of Yu. N. Demkov to the scattering theory was the discovery and exploration of so-called harmonic scattering in collaboration with I. V. Komarov, A. P. Scherbakov, and D. I. Abramov where the Euler - Cauchy mathematical theory was applied to the study of scattering of fast charged particles at small angles by electrostatic and magnetostatic targets. Recently Yuri worked on the exact solution of multistate Landau-Zener type models and superfocusing in atomic and nuclear channeling scattering. His last work on superfocusing was published in Physics of Atomic Nuclei (2009).

Professor Demkov maintained collaborations with many research institutions in the USSR (Leningrad, Moscow, Voronezh, Riga, Vilnius, Tbilisi, Chisinau, Tashkent, Minsk) and abroad (Yugoslavia, Germany, Hungary, USA, Britain, France, Japan, Netherlands, Denmark, Sweden). Starting in 1964, he often traveled for research purposes. In 1975, he spent one year as a visiting scholar at JILA (Boulder, Colorado); for the 2003-2004 academic year, he had a Mercator professorship at Goethe University (Frankfurt, Germany). He took part in many international conferences and served as a member of the program committees of the conferences on electronic and atomic collisions (ICPEAC, 1967 to 2003).

Professor Demkov founded a research group on the theory of atomic collisions at Leningrad State University. He was always ready for scientific discussions and shared his knowledge and experience with young people. He had brilliant intuition and exceptional versatility and he generated many original ideas in broad areas of physics. Some of these ideas had been elaborated by Demkov himself, his students and co-workers, and others are still waiting for further exploration.

We will remember Yu. N. Demkov for his outstanding contribution to theoretical atomic physics, his achievements as an educator, and his warm personality.