Abstract
A new concerted mechanism is proposed to explain the Cl removal from the adsorbed GaCl on the outermost As surface, by the ab initio configuration interaction (CI) calculations on the simple model system of H2GaCl+H2. The proposed reaction scheme is written as >GaCl+H2→>GaH+HCl which occurs through the single-site collision of H2 with the adsorbed GaCl on the surface. Concerted electron delocalizations induced by H2 is the driving force to proceed the reaction. The present calculation predicts that the reaction is endothermic with an energy of 29 kcal/mol and has a four-centered transition state. The estimated activation energy is 83 kcal/mol, which will be reduced by improving the present cluster model.