The (100) surfaces of alkali halides: III. Electron stimulated desorption and overall discussion

Abstract

The electron stimulated desorption of common gaseous materials from the (100) surfaces of LiF, KCl, NaF and MgO is reported. Measurements are given of the desorption rate as a function of primary electron beam energy and intensity. Most of the results are interpreted in terms of a simple model in which damage of the surface by the incident electrons allows gaseous impurities trapped in the bulk of the crystal to diffuse to the surface. The results of this set of three papers on the surfaces of alkali halides are discussed in relation to the mechanisms of epitaxial overgrowth. It is concluded that simple experiments on alkali halides are often unreliable in that the surface structure and stoichiometry depend upon a number of generally uncontrolled parameters. M and F centres are suggested as a pair of potential nucleation sites for condensing metal vapour.