Origin of structures in the low-energy single-electron continuum in calculations for ion collisions from argon

Abstract

Doubly differential cross sections for inclusive single-electron emission in $3.6 {\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{a}\mathrm{m}\mathrm{u}\mathrm{}\mathrm{Au}}^{53+}+\mathrm{Ar}$ collisions are calculated in the continuum distorted wave with eikonal initial-state approximation. Previously observed structures in the low-energy continuum are traced back to a known deficiency of the Hartree-Fock-Slater target potential that has been used in the work [R. Moshammer et al., Phys. Rev. Lett. 83, 4721 (1999)]. The structures do not occur, if the argon atom is described in terms of the optimized potential method, in which the electronic exchange interaction is treated exactly.