Electron Transfer in keV-Energy 4HE(++) Collisions. II. Formation of 4He(+)(2s) in Collisions with HE, AR, H2, and N2.

摘要

Cross sections for single-electron transfer forming the metastable state 4He(++)(2s) have been measured for a 4He(++) beam incident on thin He, Ar, H2, and N2 gas targets. The 4He(++) energy range was 7-70 keV. The experiments utilized detection of the 2s state via a delayed time coincidence between a field-induced Lyman-alpha photon and the ion itself. While the measured cross sections are believed accurate to + or - 35%, they are three times larger than the recent cross sections of Shah and Gilbody using incident 3He(++) ions. The present time-coincidence technique directly measured the fraction of the total electron-transfer cross section resulting in metastable production with results ranging between 5% and 17%. (Author)