Scaling of triple differential cross-sections for asymmetric (e, 2e) process on helium isoelectronic ions by fast electrons

Abstract

A simple scaling law is obtained for asymmetric (e, 2e) process on helium isoelectronic ions by fast electrons. It is based on treating the targets as having one active electron moving in the effective Coulomb field of the atomic core with an effective chargeZ′ = Z- 5/8. This effective charge is also used in the description of the scattered and ejected electrons. The model has been tested against other available (e, 2e) results on helium in asymmetric geometry. The scaling law is found to work reasonably well for fast incident electrons and becomes increasingly accurate as targetZ increases.