Molecular adsorption and dissociative reaction of oxygen on the Si(111)7X7surface

Reaction paths for the adsorption and dissociation of O-2 molecules on a Si (111)7X7 surface have been presented by theoretical computations. The adsor ption of an O-2 molecule produces a molecular precursor, and the subsequent O-2 dissociation leads to a stable oxidized species. An attack of another O-2 molecule on the molecular precursor also gives stable states through th e adsorption and dissociation process. In both reaction paths, small energy barriers appear before the O-2, molecular adsorption and the O-2 dissociat ion requires substantial activation energies of 1.3 eV. The electron distri butions and density,of states have been examined for several stable configu rations along the reaction paths. The characteristic properties of these co nfigurations are discussed and compared with experimental data.