Oxygen diffusion through the Ag(111) surface: A quantum chemical study by the NDDO/MC method

Atomic forms of oxygen on the (111) face of metallic silver are studied by the NDDO/MC semiempirical method. The surface (above the octahedral void) and subsurface (within the void) positions of oxygen between the first and second layers of the (111) face are investigated. The potential surface cross section is calculated for the subsurface position of oxygen. A new approach is used to take into account surface relaxation due to reaction with adsorbate. The barrier of atomic oxygen diffusion through the surface is much lower than the banier of its desorption from the surface. The correlation correction to the diffusion and desoption barrier energies is estimated by the double CI (DCIP) method. The greatest correlation effects are obtained in the desorption banier calculation.