A photoelectron diffraction and nexafs study of the structure of the methoxy species (CH 3O−) on Cu{100}

Abstract

The structural arrangement of the methoxy species (CH 3O−) on Cu{100} has been investigated by photoelectron diffraction from the O ls and C ls levels, data being collected in the scanned energy mode for emission along the surface normal, and by O and C K-edge NEXAFS. The results show that adsorption is in a low symmetry site with the oxygen atom lying between the bridge and hollow site (0.9 Å from the bridge site) but the molecular axis is oriented essentially parallel to the surface normal (with a possible tilt of about 10 ° only). The photoelectron diffraction and C K-edge NEXAFS data show that the previous assignment of a much greater tilt angle, based on O K-edge NEXAFS data, results from an oversimplified interpretation of the data. Possible reasons for the low symmetry adsorption site are discussed.