General multiple-scattering scheme for the computation and interpretation of x-ray-absorption fine structure in atomic clusters with applications toSF6,GeCl4, andBr2molecules

We present a general multiple-scattering (MS) scheme utilizing complex potentials for the calculation and interpretation of inner-shell x-ray-absorption fine structure for clusters of atoms in condensed matter with application to the case of the molecules SF 6 , GeCl 4 , and Br 2 . The method is based on the solution of the Dyson equation with a complex self-energy of the Hedin-Lundqvist type for the single-particle Green's function describing the propagation of the excited photoelectron through the system