Quantum mechanical study of H(g)+Cl–Au(111): Eley–Rideal mechanism

Beams of atomic hydrogen are known to react with halogens adsorbed on metal surfaces, and an Eley–Rideal mechanism has been suggested. The collinear reaction of gas phase H with Cl atoms adsorbed on an Au(111) surface is explored using time dependent quantum techniques. Probabilities for reaction and reflection are computed as a function of incident H energy and Cl–metal vibrational state. The time evolution is examined and a long lived intermediate is found to exist in which the Cl is bound to both the H and the metal. The probability for Eley–Rideal reaction 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 probability are in agreement with experiment.