THE INFLUENCE OF THE HOT-DIMER ADSORPTION MECHANISM ON THE KINETICS OF A MONOMER-DIMER SURFACE-REACTION

''Hot'' dimers are molecules which after adsorption dissociate and eac h of the remaining ''hot'' monomers fly apart up to a maximum distance R from the original adsorption site. The influence of the ''hot''-dim er adsorption mechanism on relevant aspects of the bimolecular catalyz ed reaction of the type A + (1/2)B2 (''hot'') --> AB is studied by mea ns of the Monte-Carlo simulation technique. The temporal evolution of both the reactant's coverages as well as the rate of AB-production is evaluated and discussed. Due to the enhanced probability of ''hot'' sp ecies for encounters with other adsorbed particles, the rate of AB-pro duction becomes faster when increasing R. This behavior may be relevan t in the dynamic of some catalyzed reactions such as for example the o xidation of carbon monoxide on transition metal surfaces, i.e. A = CO, B2 = O2, and AB = CO2 Also the sticking coefficient of ''hot'' dimers and the average distance traveled by the ''hot'' monomers are evaluat ed and discussed.