Many-Pole Model of Inelastic Losses Applied to Calculations of XANES
Eric L. Shirley, Joshua J. Kas, J. T. Vinson, N. Trcera, D. Cabaret, John J. Rehr
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 Greens 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.
, Kas, J.
, Vinson, J.
, , N.
, Cabaret, D.
and Rehr, J.
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 November 30, 2023)