The convergence of electron collisional ionization cross-section computations for atoms and ions in distorted-wave approximation

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.