First principles calculations of X-ray absorption in an ultrasoft pseudopotentials scheme: from α-quartz to high-T_c compounds

2009/06/04 by Christos Gougoussis, Matteo Calandra, Gougoussis, Christos +5
Chemistry · Materials Science · Physics and Astronomy · #Advanced NMR Techniques and Applications #Crystallography and Radiation Phenomena #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el) #X-ray Diffraction in Crystallography #cond-mat.mtrl-sci #cond-mat.str-el

paper · pdf · doi:10.48550/arxiv.0906.0897

minor corrections, some references added, 9 pages, 5 figures, to appear on Phys. Rev. B

openalex publication_date 2009/06/04 · arxiv created 2009/06/29 · arxiv updated 2009/12/01 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28

Abstract

We develop a first-principles scheme based on the continued fraction approach an d ultrasoft pseudopotentials to calculate K-edge X-ray absorption spectra in solids. The method allows for calculations of K-edge X-ray absorption spectra in transition metal and rare-earths compounds with substantially reduced cutoffs respect to the norm-conserving case. We validate the method by calculating Si and O K-edges in α quartz, Cu K-edge in Copper and in La₂CuO₄. For the case of Si and O edges in α quartz and in Copper we obtain a good agreement with experimental data. In the Cu K-edge spectra of La₂CuO₄, a material considered a real challeng e for density functional theory we attribute all the near-edge and far-edge peaks to single particle excitations.

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