Electronic energy loss and effective charge of heavy ions in different targets

Abstract

The process of stopping is conveniently described in two steps. The first step is the dynamic screening of the impacting projectile by the electron gas of the target which results in the concept of effective charge. The second is the interaction between the screened projectile and the target atoms. A model of an impacting heavy ion embedded in a jellium is used to calculate the static charge state and the effective charge of the heavy ion at the zero velocity limit based on the self-consistent density-functional theory. This effective charge of the heavy ion at low velocities is extrapolated to a higher velocity by means of the BK formula. The quantal harmonic oscillator model which takes the structures of target atoms into accounts is generalized to calculate the electronic energy loss of heavy ions colliding with three kinds of targets. The results are compared with the available experimental data.