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Multi-Pole Representation of the Dielectric Matrix



J A. Soininen, J J. Rehr, Eric L. Shirley


A good approximation for the electron self-energy or the electron quasiparticle properties is needed for an accurate calculation of x-ray absorption spectra. The GW approximation (GWA) has been found to be relatively reliable in predicting the quasiparticle energies and lifetimes in a large variety of systems. For solids, a part of a GWA calculation is the calculation of the inverse of the dielectric matrix epsilon^-1. We introduce an iterative method for calculating an accurate multi-pole approximation for epsilon^-1 and we apply it in GW calculations. Results for quasiparticle properties are presented for LiF and Si. For LiF we use these results to calculate the inelastic x-ray scattering spectra for energy loss close to the F K-edge. Other uses for this representations of epsilon^-1 will also be discussed.
Physica Scripta


energy-loss, iterative, k-edge, poles, quasiparticle, scattering


Soininen, J. , Rehr, J. and Shirley, E. (2021), Multi-Pole Representation of the Dielectric Matrix, Physica Scripta (Accessed March 4, 2024)
Created October 12, 2021