Springer Ser. Surf. Sci., 31, 21, 1993

Electron, Photon Stimulated Desorption of Negative Ions from Oriented Physisorbed Molecules

in "Desorption Induced by Electronic Transitions DIET V", eds. A.R. Burns, E.B. Stechel and D.R. Jennison (Springer Series in Surface Sciences, 31, 1993) p. 21
R.J. Guest, R.A. Bennett, L.A. Silva, R.G. Sharpe, and R.E. Palmer

we have studied electron and photon stimulated desorption of O- from oriented O2 physisorbed on graphite. Two different dissociation processes have been observed in electron stimulated desorption, dissociative attachment (DA) and dipolar dissociation (DD). Dissociative attachment is shown to be sensitive to the molecular orientation on the surface, whereas in the case of dipolar dissociation, the yield is less orientation dependent, a result we attribute to the rotation of the molecule on the surface during the dissociation process. Photo stimulated desorption of O- ions from O2/graphite may also proceed via substrate excitation and photoelectron impact on the adsorbate.



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