Abstract
Polarization dependence of resonant anomalous surface X-ray scattering (RASXS) was studied for interfaces buried in electrolytes and in high-pressure gas. We find that RASXS exhibits strong polarization dependence when the surface is only slightly modified by adsorption of light elements such as carbon monoxide on platinum surfaces. σ- and π-polarization RASXS data were simulated with the latest version of ab initio multiple scattering calculations (FEFF8.2). Based on the simulation, we find that Pt layer to C distances in the (2 × 2)-3CO structure are ∼ 2.0 Å and ∼ 1.6 Å for atop CO and 3-fold CO, respectively. Some considerations are presented for the origin of the polarization dependence in RASXS.