Emerging charge state after grazing collisions of heavy ions on SnTe surfaces

Abstract

Emerging charge states of He and Li ions impinging with grazing incidence on a SnTe surface are calculated at high impact velocities. The charge state distribution is obtained as result of the interplay of two atomic processes: electron capture from bound states of the topmost surface atoms and electron loss from the bound states of the projectile due to collisions with the surface atoms. At high energies we find that the projectile leaves the surface with a charge state larger than the quasiequilibrium charge state reached in the vicinity of the surface. We explain this behavior in terms of the different ranges of capture and loss mechanisms. As the projectile escapes from the surface, the balance between these two processes is broken: capture is no longer effective, and loss survives ionizing the projectile. Comparisons with the experiments are presented and discussed.