New mechanism for electron-stimulated desorption of nonthermal halogen atoms from alkali-halide surfaces

Abstract

Fully angular-resolved kinetic-energy distributions of alkali and halogen atoms emitted due to electron-stimulated desorption have been measured for (100) and (110) alkali-halide surfaces. An unexpected strong directional emission of nonthermal halogen atoms along the 〈100〉 axis of the investigated crystals has been found which is in contradiction to the predictions of the previously proposed ``Pooley model.'' We propose a new model involving diffusion of hot holes to the surface, and sudden localization of the excited hole at the surface of the crystal.