Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, UK
Abstract
The intense (1012 W cm-2, 800 nm) near-infrared laser desorption of benzene adsorbed on Pt{111} is reported. Velocity distributions are measured up to an adsorbate coverage of 20 monolayers. The velocity distributions reveal up to three distinct features: a hyperthermal feature with translational energy of 0.2 eV, a thermal feature and a subthermal feature. The translational energy of the hyperthermal feature is relatively independent of coverage and maintains constant desorption intensity from 4 to 20 ML. Experiments employing layered films of C6H6 and C6D6 reveal that the hyperthermal feature originates in the layers closest to the multilayer¯vacuum interface.