Electron Capture of He²⁺ from Gas Target Atoms at around a Few keV

Abstract

The single- and double-electron capture cross sections of He²⁺ have been measured for targets of Ne, Ar, Kr, Xe and N₂ in the energy range from 0.7 to 4.5 keV. The cross section curves obtained are almost flat except the double-electron capture cross section for the He²⁺–Ne case, which increases rapidly in the energy range studied. A simplified model of statistical electron transfer is introduced with the concept of interaction range and electron transfer probability to consider the collision mechanism. The He²⁺–Ar, –Kr and –N₂ collisions show that single-electron capture proceeds within the interaction range of 2×10⁻⁸ cm, mostly accompanying ionization. In the He²⁺–Xe interaction, single-electron capture is considered to be quite predominant and double-electron capture with ionization also a major process. These transfers occur with the interaction range of 4∼6×10⁻⁸ cm.