OXYGEN-ADSORPTION ON CU(110) - DETERMINATION OF ATOM POSITIONS WITH LOW-ENERGY ION SCATTERING

The position of adsorbed oxygen on Cu(110) surfaces was determined with Low Energy Ion Scattering (LEIS). The experiments were performed by bombarding the copper surface at small angles of incidence with low energy Ne+ ions (3-5 keV). Measurements of the Ne+ ions scattered by adsorbed oxygen showed regular peaks in the azimuthal distribution of the scattered ions due to a shadowing effect. From the symmetry of the azimuthal distributions it follows that the centre of an adsorbed oxygen atom on the Cu(1̄10) surface lies about 0.6 Å below the midpoint between two neighbouring Cu atoms in a 〈001〉 row. A comparison of the azimuthal distributions of Ne+ ions scattered from clean Cu surfaces and oxygen-covered Cu surfaces showed that hardly any surface reconstruction had occurred in the oxygen-covered surfaces. The applied method seems to be an appropriate one for locating adsorbed atoms because it uses only simple qualitative considerations about azimuthal distributions of scattered ions. © 1979.