Surface-induced dissociation in H 2+ collisions studied with ion impact electron spectroscopy

Abstract

The electronic transition processes in slow collisions of small molecular ions with metal surfaces are discussed briefly. Examples will be given where molecular dissociation is induced by electronic transitions between the projectile and the surface. It will be demonstrated how information on surface-induced dissociation (SID) can be obtained from ion impact electron spectroscopy. For slow collisions (mostly 50 eV) of H 2 + with tungsten surfaces the following channels for SID can be identified from the analysis of the ion impact electron spectra: (1) on clean tungsten, the neutralization of the projectile ions into the repulsive state H 2(b 3 Σ u +), both resonantly and by Auger capture; and (2) for alkali covered tungsten, in addition to direct H 2(b 3 Σ u +) population, both Auger de-excitation to H 2(b 3 Σ u +) and mechanical dissociation of hydrogen states, correlating with H( n = 2) + H(1s).