Energy-loss spectra of swift ions

Abstract

Analytical expressions for the energy-loss spectrum of swift ions are presented. The approximations are exceedingly accurate (both in the main part of the spectrum and in the tails) and cover the whole range of energy losses small compared to the primary energy but large on an atomic scale. The results are based upon the comprehensive Bothe–Landau formula. A significant generalization of Landau's approach and the steepest-descent technique are applied at smaller and larger path-lengths, respectively; the regions of validity of the two turn out to overlap. On the basis of these approximations, simple and accurate expressions for the mean-to-peak interval are found.