Universal features of the concentration dependence of alkali ions desorption induced by electronic transitions

On the basis of a simple model, proposed by us previously, the alkali metal positive ions yield induced by electronic transitions has been calculated. It was supposed that the yield is proportional to the product of the alkali adatoms' concentration and the ion survival probability. The Menzel-Gomer-Redhead model for the survival probability has been used. Concentration effects are incorporated into the quasi-level width of desorbing particles. Theoretical results for the Li+ and Na+ ions desorption from the silicon covered tungsten and iridium substrates are in good agreement with experimental data, as well as for the oxidized tungsten surfaces achieved previously. (C) 1998 Elsevier Science B.V. All rights reserved.