Adsorbate structural determination of CO and HCNH using C K-edge NEXAFS on W(100)-(5 × 1)-C

Abstract

The adsorption structures of CO, HCN, and HCNH on W(100)-(5 × 1)-C were determined using near edge X-ray absorption fine structure. A normalization technique that removes structures in the spectra that arise from the carbon adiayer as presented. CO is bound perpendicular to the surface and has a bond length of 1.13 ±0.05 Å. The positions of the edge jumps at the C K- and O K-edges relative to the C(1s) and O(1s) X-ray photoelectron spectroscopy binding energies are significantly different. The differences are attributed to the fact that CO bonds weakly to the surface through the carbon atom, with little back bonding from the carbon-modified metal surface. The HCNH intermediate formed by heating to 475 K is oriented with its C-N bond vector inclined at an angle of 58° ±10° with respect to the surface normal and a C-N bond length of 1.34 ±0.04 Å. This species is suggested to bond via the carbon atom which is sp 2 hybridized.