Electron impact ionization of ground-state Be-like rare gas ions

Abstract

Detailed calculations for electron impact ionization including direct ioniza- tion (DI) and excitation autoionization (EA) processes along the ground-state Be-like rare gas ions have been performed by using relativistic distorted wave (RDW) approx- imation. The DI contribution from 2s shell and the EA contributions from inner-shell electron impact excitations of 1s−nl (n≤12, l≤4) were considered. The contribution of DI is a little more than 90% to the total electron impact ionization cross section. The main EA contribution comes from 1s−2p electron impact excitation channel. The EA contribution relative to DI contribution first increased and then decreased as the atomic number Z increases in Be-like rare gas ion. The EA rate coefficients are given for all ground-state Be-like rare gas ions as a function of impact electron temperature. PACS: 34.80.Dp, 32.80.Hd