Oxygen chemisorption and incorporation on transition metal surfaces

Abstract

Abstract The effective medium approach is used to calculate the full adiabetic ground state potential energy surface for an oxygen atom outside and inside the Ni(100) and (111) surfaces. For chemisorbed oxygen, bond lengths and vibrational frequencies are deduced and compared to experiment. The oxygen chemisorption energies are calculated for all the 3d transition metals and the trends are discussed. For oxygen incorporated between the first and second layers of the Ni(100) and (111) surfaces, the main result is the finding of a very strong, lattice mediated, attractive oxygen-oxygen interaction. The implications of this for surface oxide nucleation and growth are discussed. The activation barrier for the oxygen incorporation process couples very strongly to the fluctuations of the nickel lattice. For oxygen on Ni(111) this results in an apparent activation energy of only one tenth the static lattice value. Finally, we present results for subsurface hydrogen and the hydrogen incorporation reaction.