Finite Temperature Effects on the X-ray Absorption Spectra of Crystalline Aluminas from First Principles

2022/06/21 by Harper, Angela F., Monserrat, Bartomeu, Morris, Andrew J.
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)

paper · doi:10.48550/arxiv.2206.10448

Abstract

By including phonon-assisted transitions within plane-wave DFT methods for calculating the X-ray absorption spectrum (XAS) we obtain the Al K-edge XAS at 300 K for two Al₂O₃ phases. The 300 K XAS reproduces the pre-edge peak for α-Al₂O₃, which is not visible at the static-lattice level of approximation. The 300 K XAS for γ-Al₂O₃ correctly describes two out of the three experimental peaks. We show that the second peak arises from 1s to mixed s-p transitions and is absent in the 0 K XAS. This letter serves as a basis for future applications, as the method is generalizable to any atom and edge.

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