Z1 oscillations in stopping of atomic particles

Abstract

The measured stopping cross sections for atomic projectiles in various materials show Z1 oscillations, a more or less periodic dependence of the stopping on Z1, the atomic number of the projectile.These oscillations have a larger amplitude when the projectiles are channeled in single crystals than when they are not.In this paper it is shown that the oscillations are a size effect, i.e., the larger an atom the more it is ionized and the greater is the stopping. Calculation of stopping of low [Formula: see text] channeled particles in tungsten and silicon give qualitative agreement with experiment: the maxima and minima are in the right places, and vary in the right way, but the calculated amplitude of oscillation is too small. Possible explanations for the amplitude discrepancy are suggested.