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 NDDOIMC semiempirical method. The surface (above the octahedral void) a nd subsurface (within the void) positions of oxygen between the first and s econd layers of the (111) face are investigated. The potential surface cros s section is calculated for the subsurface position of oxygen. A new approa ch is used to take into account surface relaxation due to reaction with ads orbate. The barrier of atomic oxygen diffusion through the surface is much lower than the barrier of its desorption from the surface. The correlation correction to the diffusion and desorption barrier energies is estimated by the double CI (DCIP) method. The greatest correlation effects are obtained in the desorption barrier calculation.