Stochastic theory of equilibrium charge-state distributions of heavy ions in gases

Abstract

A stochastic theory of equilibrium charge-state distributions is presented and its explicit relation to the underlying single ion-atom collision is shown. In this approach each individual collisions is regarded as a stochastic process in which either loss or capture of one or several electrons occurs. The result is a universal representation of charge-state distributions which reproduces the observed asymmetries in terms of a single energy-independent parameter. A statistical analysis shows that this parameter, which is related to a correlation function in single collisions, assumes essentially two values only, leading to the log normal and gamma distributions, respectively. Furthermore the theory predicts a scaling law for single collisions which was fulfilled by the recent cross section measurements of Astner and co-workers (1984).