Evidence for photoelectron backscattering by interstitial charge densities

The presence of oscillatory structures in the atomic x-ray absorption background is reported for the first time for surface-EXAFS of cN/Cu(100) and N/Cu(110). Systematic analysis of this feature (AXAFS) and comparison to theory yields new information on the electronic structure of the adsorbate - substrate surface bond. Also, angle and temperature dependent analysis of the AXAFS peak provides qualitative information about interstitial charge density distribution.