Perturbations, inhibition, and promotion of ultraviolet surface photochemistry: CH3 Br on Br/Ni(111)

The inhibition and perturbations of surface photochemistry, due to the coupling of the excited state to the surface, are discussed as it pertains to CH3 Br adsorbed on nickel. Photofragmentation of CH3 Br was observed on a brominated Ni(111) surface, with the fragmentation process being strongly perturbed at low coverages. The perturbations are attributed to charge transfer processes. Direct photofragmentation was observed as well as a surface specific dissociative electron attachment channel. Cross section values are reported for fragmentation at 193 and 248 nm.