Stimulated desorption

Abstract

The fundamentals of stimulated desorption by electronic excitations is reviewed. Specifically this includes electron- and photon-stimulated desorption and electronic processes in sputtering and secondary-ion emission. The general experimental observables include desorption thresholds, chemical effects on desorption yields, ion energy distributions, ion angular distributions and the spectral dependence of the desorption yield. Mechanisms for desorption involve both direct excitation of valence levels and indirect excitations which proceed via core-hole excitation. The Auger decay of core-holes can create multiply ionised and excited states which are highly local, contain a large amount of energy and have intrinsically long lifetimes. A general discussion of the properties of these complex states is given, together with a discussion of their applicability to different types of covalent and ionic states. A number of examples of case studies in ion desorption are given, including CO and NO on metals, hydrogen on surfaces, oxides and oxygen on surfaces and desorption from cryosolids.