Photodesorption of NO from graphite(0Â 0Â 0Â 1) surface mediated by silver clusters

The influence of the size and shape of nanometer-scale silver particles on the photodesorption of NO from a graphite(0 0 0 1) surface has been investigated. The initial photodesorption yield from a silver precovered surface increases upto 20 times compared to the clean graphite surface under irradiation with 355 nm photons. The yield fluctuates with cluster size and shows atleast one pronounced maximum. The observation is attributed to increased optical absorption due to particle plasmon excitations. Possible mechanisms for dissipation of the plasmon energy leading to NO desorption are discussed. The mechanism behind the photodesorption of NO from clean graphite(0 0 0 1) is also investigated and believed to be a substrate-mediated process.