Zajac T. The theoretical description of the quasi-stationary states, which are located above the threshold of excited ion generation, in the problem of ionization of helium by fast electrons.

TThe thesis contains the formulation of the method of interacting configurations in complex number representation. The method is applied to the problem of electron impact ionization of atoms (for example, a helium atom). The developed approach allows analyzing the decay of the m quasi-stationary states into the n open channels. The program package for numerical calculations is created. The processes of direct and resonant ionization of the helium atom above the threshold N=2 are investigated. The spectroscopic characteristics of autoionizing states, which converge to the third threshold of the helium atom, are calculated. The influence of different physical processes on the spectroscopic characteristics of autoionizing states is studied. Generalized oscillator strength for resonant transition of partial states for the helium ion with n=1 and n=2 by the method of interacting configurations in complex number representation is calculated. It allows us to find the kinematic conditions, for which the preferable occupation of the excited states of the residual ion He+ with n=2 over the ground state He+ - n=1 is observed. The positions and width of the singlet 1S, 1P, 1D, 1F quazistationary states, which converge to the threshold N=3 of the helium atom, are found