Scattering of ions by the real single crystal surface damaged under ion bombardment

Abstract

The experimentally observed ion scattering within the shade zone, and the existence of a discrete structure of the scattered ion spectrum in a wide range of glancing angles, cannot be explained within the framework of the concept of an ideal surface. The scattering of ions on such defects of the structure as individually protruding atom steps, pairs of atoms and atomic vacancies in surface chains can be represented in a model as successive collisions, with two atoms located one from the other at distances D divisible by the interatomic distance in an ideal crystal. The results of electronic computer calculations for a two-atom model have been compared with analytical evaluations, and the sphere of application of the latter has been estimated. Calculations based on the real single crystal surface damaged under ion bombardment make it possible to explain the experimental data. Consideration for the real surface and the predominant ionization of the particles which had been subjected to a lesser number of collisions calls for serious attention to the two-atom model.