Many-Pole Model of Inelastic Losses Applied to Calculations of XANES

Published

December 16, 2009

Author(s)

Eric L. Shirley, Joshua J. Kas, J. T. Vinson, N. Trcera, D. Cabaret, John J. Rehr

Abstract

Conventional Kohn-Sham band-structure methods for calculating deep-core x-ray spectra typically neglect photo-electron self-energy effects, which give rise to an energy dependent shift and broadening of the spectra. Here an a posteriori procedure is introduced to correct for these effects. The method is based on ab initio calculations of the GWself-energy using a many-pole model and a calculation of the dielectric function in the long wavelength limit using either the FEFF8 real-space Green’s function code, or the AI2NBSE interface between the NIST Bethe-Salpeter equation solver (NBSE) and the ABINIT pseudopotential code. As an example the method is applied to core level x-ray spectra of LiF and MgAl2O4 calculated using (respectively) OCEAN, an extension of the AI2NBSE code for core level excitations, and the PARATEC pseudopotential code with the core-hole treated using a super-cell. The method satisfactorily explains the discrepancy between experiment and calculations.

Citation

Journal of Physics: Conference Series

Volume

190

Pub Type

Journals

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DOI Link

Keywords

Many-Pole Model, Self-Energy, X-ray

Citation

Shirley, E. , Kas, J. , Vinson, J. , , N. , Cabaret, D. and Rehr, J. (2009), Many-Pole Model of Inelastic Losses Applied to Calculations of XANES, Journal of Physics: Conference Series, [online], https://doi.org/10.1088/1742-6596/190/1/012009 (Accessed October 11, 2024)