Orientation of Benzene and Phenoxy on the Polar ZnO(0001)−Zn Surface

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the C K -edge has been used to investigate the orientation of benzene and phenoxy on the Zn-terminated basal face of ZnO. From these results, we deduce that benzene is oriented more or less parallel to the surface, bonding through its π orbitals, whereas the phenoxy formed on exposure to phenol is bonded through O atop Zn. Benzene has an apparent tilt angle of the ring plane with respect to the surface of 11 ± 5°, whereas exposure to phenol results in a tilt angle of 35 ± 5°. These tilt angles are similar to those obtained after adsorption on metal surfaces. The data are consistent with a stabilization mechanism of this polar surface which does not involve a substantial reconstruction.