APPLICATION OF A NOVEL MULTIPLE-SCATTERING APPROACH TO PHOTOELECTRON DIFFRACTION AND AUGER-ELECTRON DIFFRACTION

We apply a new separable Green's function matrix method due to Rehr and Albers [Phys. Rev. B, 41 (1990) 8139] to a multiple scattering treatment of photoelectron diffraction and Auger electron diffraction. This cluster-based method permits building up successive orders of scattering and judging the approach to convergence in a convenient and time-saving way. We include multiple scattering up to tenth order and can treat photoelectron emission from any initial state (s, p, d, or f) with full final state interference, as well as Auger emission in the s final state approximation. This new approach is used to simulate emission from linear and bent chains of atoms, from epitaxial overlayers and multilayer substrates and from atomic and molecular adsorbates. The method appears to have a broad range of utility. We also discuss the types of geometric structures for which multiple scattering effects must be considered, and the nature of the effects expected.