Low energy ion-surface scattering - physics and applications

This paper reviews some recent developments in low energy ion scattering, i.e. the spectrometry of noble gas ions of about 100 to 2000 eV backscattered from solid surfaces. From the physical processes involved the neutralization at the surface and in particular the oscillatory structure in the energy dependence of scattered ion yields has prompted a number of investigations. The interpretation of these structures by quasiresonant charge transfer in binary collisions seems to be established. Some sensitivity to the chemical environment is found. Ion scattering has a particular potential for the analysis of adsorption layers. Surface structures and positions of adsorbed atoms and molecules have been investigated by this method. Examples are given in which its specific surface sensitivity and the corresponding shadowing effects are utilized. (Auth.)