Effect of hydrogen adsorption on the x-ray absorption spectra of small Pt clusters

Hydrogen adsorption on Pt6Hn clusters leads to striking changes in the Pt L -2.3 x-ray absorption spectra. These effects are interpreted using a self-c onsistent 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 we ak. The origin of both effects is traced to the change in the local Pt pote ntial due to Pt-H bonding.