0000000000768838
AUTHOR
C. R. Natoli
MultiChannel Multiple Scattering Theory for XAFS. Application to L2,3 Edges of Ca
We present a multichannel extension of the multiple scattering method for x-ray absorption fine structure (XAFS) spectroscopy that allows to take account of atomic multiplet-like electron correlation effects in condensed systems, on the basis of ab initio electron structure calculations. The formalism is outlined and an application to near-edge XAFS at the L2,3 edges of Ca metal is presented. In this system, the experimentally observed branching ratio deviates strongly from that obtained from the standard (one-electron) approach to XAFS. This is due to that fact that one-electron theory neglects the multiplet coupling between the photo-electron and the 2p core-hole. Within the multi-channel…
Multiple scattering approach for two-electron resonant emission studied by angle-resolved coincidence spectroscopy.
International audience; We have developed a generalization of the multiple-scattering formalism to deal with Auger-photoelectron coincidence spectroscopy APECS in the solid state. We have merged the exact atomic treatment of the angular correlations between the two electrons and the single-particle approach, on which the multiplescattering description of condensed matter relies. This allows the recovering, even in extended systems, of the entangled form of the electron-pair wave function characterizing the coincidence angular diffraction pattern. In the atomic limit our formalism correctly reproduces the cross section, as calculated within the statistical-tensors approach, usually employed …