Atomic adsorption of oxygen on Cu(111) and Cu(110)

We have studied angle-resolved inverse photoemission ( = 9.7 eV) after room temperature adsorption of oxygen on Cu(111) and Cu(110). On Cu(111) exposure to 500 L induces a band (3.0 eV aboveE _F at) which shows clear dispersion (1.0 eV) to higher energies for off normal incidence. Since no LEED superstructure is seen for that system, our results present strong evidence for the presence of short-range surface order. Two adsorbate bands are identified (2.8 eV and 6.3 eV at) on Cu(110)p(2×1)-O. Our results are in good agreement with a long-bridge adsorption site.