Impact-parameter-dependent energy loss and straggling at low-energy light-ion scattering

Abstract

Inelastic effects in ion-surface scattering have been investigated using the recently developed one-shell dielectric function together with the shell-wise local electron density model. We propose a new form of the impact-parameter dependence of the electronic energy loss and straggling of light ions at low velocities. Herein a formula of the impact-parameter dependent energy straggling for light ions is presented for the first time. The derived formula shows that the energy loss decreases with increasing impact parameter more gradually than the Oen-Robinson formula. As an example, the case is considered where a He + ion is scattered from a Pb surface. The calculated result on the energy loss is in good agreement with the data.