Excitation of autoionizing states of helium-like ions by high-energy electron scattering

Abstract

We have evaluated the cross sections for two-electron excitations of helium-like ions into the autoionizing ( 2 s 2 p ) 1 P states by high-energy electron scattering. The problem is solved to leading orders of non-relativistic perturbation theory. The analytical formulas for cross sections are deduced in the form of universal scaling. The resonant electron-emission yield is calculated with taking into account the interference between direct and sequential ionization channels. A comparison between the present results and the experimental data for helium atom is made.