IDENTIFICATION OF 2 TILTED ADSORBED MU-2-METHOXY SPECIES ON NI(110) USING RAIRS

Two different adsorbed methoxy species on Ni{110} are identified using reflection absorption infrared spectroscopy both of which are twofold coordinated and tilted with respect to the surface normal. One methoxy species is adsorbed onto short bridge sites on the close-packed rows, with a large tilt angle in the [001] direction. The other methoxy species is adsorbed at a long bridge site across the close-packed rows and tilted with a smaller angle in the [110BAR] direction. We also report a remarkable similarity between the infrared data for methoxy adsorption on the same single crystal faces of Ni and Cu, indicating that the nature of the chemisorbed species is determined by the site symmetries on the different planes, and not by the metal itself.