Electron stimulated desorption in the Anderson model

Abstract

The results of a previous paper for the self-energy of the single particle Green's function of an adsorbate on a metal are applied to the process of electron stimulated desorption. In particular the decay rate of the excited state responsible for desorption is calculated as a function of the distance of the adsorbate from the surface. The decay rate W( r) can be parametrized approximately as W( r) = w 0 exp(−α r) ( r is the distance from the equilibrium position of the adsorbate). In contrast to earlier speculations turn out to be rather small ( W 0 = 0.7 to 0.85 eV, α = 1.4 to 1.75 Å −1 for hydrogen on tungsten). The quantum effects of desorbing hydrogen found for larger values of α then are strongly reduced.