THEORETICAL-STUDY OF O ADLAYERS ON RU(0001)

Recent experiments performed at high gas partial pressures indicate th at ruthenium can support unusually high concentrations of oxygen at th e surface. To investigate the structure and stability of high coverage oxygen structures, we performed density functional theory calculation s, within the generalized gradient approximation, for O adlayers on Ru (0001) from low coverage up to a full monolayer. We achieve quantitati ve agreement with previous low-energy electron diffraction intensity a nalyses for the (2x2) and (2x1) phases and predict that an O adlayer w ith a (1x1) periodicity and coverage Theta=1 can form on Ru(0001), whe re the O adatoms occupy hcp-hollow sites.