Electron transfer inp−He+andHe2+-H collisions using a Sturmian basis

Abstract

Total cross sections are reported for electron transfer into all bound states in collisions of protons with $^{4}\mathrm{He}^{+}$ ions and $^{4}\mathrm{He}^{2+}$ ions with H atoms at center-of-mass energies from 4 to 120 keV and 4 to 40 keV, respectively. The coupled-state calculations employ 19-24 Sturmian basis functions. Convergence of cross sections with respect to the size of this basis has been studied, and total cross sections are estimated to be converged to a few percent. A comparison is made with molecular-state, atomic-state, classical, and experimental results. In the energy region of overlap, Sturmian-state results and plane-wave-factor, molecular-state results agree to within 9% except for the $p\ensuremath{-}{\mathrm{He}}^{+}$ process at 14 keV, where the Sturmian results are 37% larger, probably reflecting the need to include the continuum which was omitted in the molecular calculations. There is also a similar discrepancy with the experimental results of Peart, Grey, and Dolder; these Sturmian results, however, do tie in with the experimental results of Angel, Sewell, Dunn, and Gilbody at higher energies.