Effect of Hydrogen Adsorption on the X-Ray Absorption Spectra of Small Pt Clusters

Abstract

Hydrogen adsorption on ${\mathrm{Pt}}_6{\mathrm{H}}_n$ clusters leads to striking changes in the Pt $L_{2,3}$ x-ray absorption spectra. These effects are interpreted using a self-consistent real space Green's function approach. Calculations show that they are due largely to changes in the atomic background contribution to x-ray absorption (i.e., atomic x-ray absorption fine structure) and to reduced Pt-Pt scattering at the edge, while Pt-H multiple scattering is relatively weak. The origin of both effects is traced to the change in the local Pt potential due to Pt-H bonding.