Charge-transfer photodissociation of adsorbed molecules via electron image states.
The 248 and 193 nm photodissociations of submonolayer quantities of CH(3)Br and CH(3)I adsorbed on thin layers of n-hexane indicate that the dissociation is caused by dissociative electron attachment from subvacuum level photoelectrons created in the copper substrate. The characteristics of this photodissociation-translation energy distributions and coverage dependences show that the dissociation is mediated by an image potential state which temporarily traps the photoelectrons near the n-hexane-vacuum interface, and then the charge transfers from this image state to the affinity level of a coadsorbed halomethane which then dissociates.
Jensen
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Physics Department, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada. ejensen@unbc.ca