ION-SURFACE INTERACTIONS IN THE ELECTRON-STIMULATED DESORPTION OF CL-2( FROM CL)SI(111)-7X7/

Cl+ electron-stimulated desorption energy and angular distributions ar e collected from Si(111)-7 X 7 surfaces exposed to Cl-2. The results o f these measurements are fitted to a model that accounts for variation s in the surface work function, ion-surface image-charge interactions, and ion neutralization. From the fits, the strength of the image-char ge interaction and the angular dependence of the neutralization are de termined. The ideas presented here concerning the motion of ions in th e vicinity of a surface are generally valid for ah ion-surface interac tions.