Auger electron-ion coincidence study for H 2O adsorbed on [formula omitted] at 80 K

Abstract

Electron stimulated ion desorption induced by core level excitations has been studied for H 2O condensed on a SiO 2 Si(111) surface at 80 K [H 2O/SiO 2/Si(111)] by using Auger electron-ion coincidence spectroscopy. The coincidence H + yield from the H 2O/SiO 2/Si(111) was found to be enhanced at the electron kinetic energies corresponding to O(KVV) Auger transitions. This result presents direct and clear evidence of an Auger stimulated ion desorption mechanism accompanied by the cleavage of a covalent bond. A KV NB V NB Auger process is concluded to lead to ion desorption less efficiently than KV BV NB and KV BV B processes (V NB and V B represent the non-bonding and bonding valence orbitals, respectively).