Energy dependence of scattered ion yields in ISS

Abstract

Scattered ion yields as a function of primary ion energy in the range from 200 to 2500 eV have been measured for He+, Ne+, and Ar+ scattering from a variety of solid surfaces. The energy dependence of these yield curves contains information about the electronic states of surface atoms which complements normal ISS data. In addition, changes in the surface‐atom chemical environment can be manifested as changes in the yield curve. A preliminary classification of yield curve shapes is proposed based on two considerations. First, does the target atom have an electronic state with a binding energy within approximately ±10 eV of the bombarding species’ first ionization potential? Second, if the first criterion is satisfied, what are the orbital symmetries of this electronic state and the vacant ionic state?