The structure of the oxygen-covered Cu{110} surface was investigated using low energy (keV region) Ne+ and H2O+ bombardment. This involved measuring scattered Ne+ and O− ions and of positively and negatively charged oxygen recoil ions. The adsorbate-induced structure was studied by using methods described earlier. The oxygen-covered surface was found to be reconstructed. The reconstruction could be described by the so-called missing-row model, in which all <100> atom rows adjacent to the oxygen-containing <100> rows have disappeared from the surface. The lateral position of chemisorbed oxygen atoms was found in the bridge position in the <100> surface row. The Cu atoms in the oxygen-containing surface rows were in the same positions as they were on the clean surface. This reconstruction could explain the (2 x 1) low-energy electron diffraction pattern observed for oxygen-covered surfaces, since the unit cell in the reconstructed surface was twice as large as the unit cell of the clean surface. The maximum coverage degree for exposures up to 100L was found to be one oxygen atom per unit cell of the reconstructed surface. From the differences between the photograms of O− and of O+ recoil ions it was deduced that there could be a second kind of adsorption site in the first two surface layers where oxygen could become chemisorbed. It was suggested that this site was near the second layer, below the position of the missing row in the surface.

Reconstruction of the Oxygen-Covered Cu{110} Surface Identified with Low Energy Ne+ and H2O+ Ion Scattering. R.P.N.Bronckers, A.G.J.de Wit: Surface Science, 1981, 112[1-2], 133-52