Coupled channel treatment of the L-shell ionization in ion-atom collisions

The deviations of the experimental L-subshell ionization probabilities relative to the semiclassical approximation are discussed in terms of couplings between the target atomic states during the collision by means of a relativistic one-centre coupled channel formalism with hydrogenic wavefunctions. Numerical results are compared with experimental data for systems He+Pt, Ne+Pt, Ne+Yb at 0.9 MeV amu-1 and S+Au at 1 MeV amu-1. A simple inclusion of the screening effect presented in this work yields a major improvement in the description of the L-shell ionization probabilities. The intra-L-shell couplings modify slightly the ionization probabilities for light projectiles but they have a marked effect for heavier projectiles. The couplings between the L and M shells were also included, but they were found to have only a small influence as compared with intra-L-shell couplings.