Electronic structure and surface reconstruction of adsorbed oxygen on copper(0 0 1)

The electronic structure of the c(2 × 2) and the missing row (22×2)R45° phases of chemisorbed O on Cu(0 0 1) at a coverage of 0.5 monolayers has been calculated using a full-potential semi-infinite embedding technique. Calculations are made over a range of Cu–O layer spacings, and from the change in the work function, the effective charge on O is obtained. The effective charge is the same for both phases of the O/Cu(0 0 1) surface with a value of −0.3|e| on O, and consequently too small to drive any surface instability. The angular momentum-resolved density of states and energy-resolved charge densities are used to describe the binding and the spatial electronic overlap at the surfaces. In the reconstructed (22×2)R45° phase the O and the surface Cu atoms undergo displacements, which optimises the bonding.