The 0.5ML oxygen-induced reconstruction of the Rh(100) surface was investigated using surface X-ray diffraction. The rhodium atoms in the surface layer adopted a “clock” reconstruction with an in-plane displacement of the surface-layer Rh atoms of dRhxy = 0.19Å. The oxygen atoms were found to be situated in the so-called diamond site rather than the rotated fourfold site on either side of the hollow site, with an in-plane displacement of 0.20Å This supported the conclusions of density-functional theory and low-energy-electron-diffraction work.

Surface X-Ray Diffraction Study of the Rh(100)(2 x 2)-O Reconstruction. A.G.Norris, F.Schedin, G.Thornton, V.R.Dhanak, T.S.Turner, R.McGrath: Physical Review B, 2000, 62, 2113-7