Investigation of the oxygen chemisorption state in thep(2×2)andc(2×2)phases on Ni(100) with He scattering

Analyses of He-diffraction data show that the oxygen adatoms produce well-separated corrugation hills with the same height and width in both the $p(2\mathrm{}\times 2)$ and $c(2\mathrm{}\times 2)$ phases on Ni(100). This confirms that oxygen chemisorbs in both phases in the same crystallographic and electronic configuration. The shape of the adatom corrugation requires a prolate charge distribution around each oxygen and should provide an important test as to the recently disputed electronic nature of the oxygen-substrate bond.