Oxygen induced reconstruction of the Rh(100) surface: General tendency towards threefold oxygen adsorption site on Rh surfaces

On the basis of a low energy electron diffraction I-V structural investigat ion, the surface geometry of the Rh(100) + (2 x 2)-2O phase has been determ ined. The oxygen is found to adsorb in an unusual threefold site of the rho mbi created by the reconstruction of the first rhodium layer, producing a p g symmetry, in agreement with theoretical predictions but at variance with previous experimental conclusions. Our result indicates that there is a str ong tendency of oxygen to adsorb in threefold sites on all Rh surfaces. [S0 031-9007(99)09340-0].