The original file was a draft of a letter of reference, later it was edited and renamed.

Collaboration with V. S. Popov (ITEP, Moscow)

A. Sergeev met V. S. Popov in 1982 at a Workshop in Riga when A. S. was a young researcher in the field of quantum mechanics and atomic physics. In 1986 they began their collaboration on perturbative and semiclassical methods for bound, and especially resonant states. At present they have over 20 joint publications in ZhETF, Physics Letters, Yad.Fiz., etc.

The most important A. S. achievements in this area are as follows.

1. Calculation of high orders of perturbation theory for screened Coulomb potentials by Sturmian approach and generalization of this technique to Dirac equation.
2. Summation of divergent perturbation series by means of Padé and Padé - Hermite approximants and detailed investigation of their convergence.
3. Semiclassical 1/N-expansion for discrete spectrum of three-body system.
4. Development of 1/n-expansion for quasistationary states, including the Stark resonances in a hydrogen atom.
5. Investigation of large orders of 1/n-expansion in quantum mechanics.

At present, A. S. is a researcher in the field of quantum mechanics, atomic physics and computational methods. Further achievements in the above areas are expected.

See also Unpublished reports for V. S. Popov.