QUANTUM-MECHANICAL STUDY OF H(G)-AU(111) - ELEY-RIDEAL MECHANISM(CL)

Beams of atomic hydrogen are known to react with halogens adsorbed on metal surfaces, and an Eley-Rideal mechanism has been suggested. The c ollinear reaction of gas phase H with Cl atoms adsorbed on an Au(111) surface is explored-using time dependent quantum techniques. Probabili ties for reaction and reflection are computed as a function of inciden t ii energy and Cl-metal vibrational state. The time evolution is exam ined and a long lived intermediate is found to exist in which the Cl i s bound to both the H and the metal. The probability for Eley-Rideal r eaction is found to be small, on the order of a few to several percent , due primarily to the mass mismatch. The vibrational distribution of the product HCl and the temperature dependence of the reaction probabi lity are in agreement with experiment.