Long-range ordered acetate structure on Cu(110)

A chemisorbed layer prepared by exposing a clean Cu(110) surface to acetic acid, CH3COOH, at room temperature was studied by LEED and X-ray photoelectron diffraction (XPD). LEED shows a well ordered pattern with an oblique ((4)(1) (-)(1)4) unit cell. The equivalent oxygen coverage is 0.75 corresponding to three acetate species per unit cell. Polar angle O ls and C Is intensity distributions measured in four different azimuths for this layer show a large number of peaks which can be correlated with an ordered array of acetate species of two different configurations. A structure model for the acetate layer is proposed on the basis of LEED and XPD data. Single scattering model calculations carried out for this model show good agreement with experiment.