Ab initio and transition state theory studies of the energetics of H atom resurfacing on Ni(1 1 1)

Ab initio methods based on density functional theory are used to compute the potential energy surface for the motion of H from the subsurface onto the Ni(1 1 1) surface. Transition state theory is used to calculate rate constants for this resurfacing. The influences of tunneling and lattice relaxation are computed and discussed, and comparisons are made with measured vibrational and thermal desorption spectra. Due to the metastable nature of the subsurface octahedral site, the resurfacing H has an excess energy of roughly 1 eV. The resulting hot and highly mobile atoms can engage in unique chemistry with surface-adsorbed species.