The problems of convergence of electron ionization cross-sections of atoms and ions in distorted-wave approximation are considered. The convergence justifies the applicability of the approximation for calculating the cross sections for impact ionization of ions and molecules by electrons in gas-plasma formations. Discrete and continuous electron wave functions needed for cross-section computation are calculated in the self-consistent potential obtained upon quantum-statistical Hatree-Fock-Slater model. It is shown using the case of nitrogen atoms and iron ions that the summation index limits in calculations substantially depend on electron energy. It has considerable meaning on optimization of computations and execution capabilities of batch cross-section calculations for a wide range of electron energies and a broad set of atomic elements.

impact ionization, cross-sections, distorted wave approximation, quantum-statistical models of plasma

Mathematical modelling in actual problems of science and technics

Chetverushkin Boris Nikolaevich,  ,  orcid.org/0000-0003-1216-5438,  KIAM RAS

Gasilov Vladimir Anatolievich,  ,  orcid.org/0000-0001-7574-4061,  KIAM RAS

Zhukovsky Mikhail Evgenievich,  ,  orcid.org/0000-0001-5886-3026,  KIAM RAS

Zakharov Vasily Sergeevich,  ,  orcid.org/0000-0002-4865-9635,  KIAM RAS

Markov Mikhail Borisovich,  ,  orcid.org/0000-0002-3428-9688,  KIAM RAS