Ion Desorption by Core-Hole Auger Decay

Abstract

We present evidence for a fundamentally new mechanism for impact-induced desorption, viz., core-hole Auger decay. We thereby explain why observed thresholds for electron-stimulated desorption (ESD) of positive ions (${\mathrm{O}}^{+}$, O${\mathrm{H}}^{+}$, and ${\mathrm{F}}^{+}$) from certain $d$-band metal oxides (Ti${\mathrm{O}}_{2}$, ${\mathrm{V}}_{2}$${\mathrm{O}}_{5}$, and W${\mathrm{O}}_{3}$) correlate in energy with the ionization potential of the highest-lying atomic core levels. We conclude that electron-stimulated desorption is in many interesting cases an atom-specific, valence-sensitive probe of surfaces.