The 1s–2s and 1s–2p excitation of helium ions by electron impact

Abstract

The electron impact excitation of He+ to the n = 2 level is studied using two variants of the polarized orbital method, one due to Daskhan et al. and the other due to Temkin and Lamkin. The present results for 1s–2p total excitation cross sections are in fair agreement with the measured values. For the 1s–2s excitation, our values fail to reproduce the more elaborate theoretical prediction by Morgan near the threshold energies.