Role of surface-dimer and gas-phase excitation models in electron-stimulated desorption of ions from sodium chloride (1 0 0) crystals

Abstract

The desorption of Na+ under electron irradiation at low energies (<1 keV) is reported. Electron-stimulated desorption of alkali atoms from alkali halides is described in terms of two distinct mechanisms of desorption. One being the gas-phase excitation model and the other, the surface-dimer model. The dimer model has been used to explain excited-state desorption from alkali halides. Desorption signatures of Na+ as functions of temperature are presented here for the first time. Comparison with Na• desorption suggests that a surface reaction process, similar to the dimer model, is significant for Na+ desorption.