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arXiv · 2206.10448

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

Angela F. Harper·Bartomeu Monserrat·Andrew J. Morris
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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 Al$_2$O$_3$ phases. The 300 K XAS reproduces the pre-edge peak for $\alpha$-Al$_2$O$_3$, which is not visible at the static-lattice level of approximation. The 300 K XAS for $\gamma$-Al$_2$O$_3$ 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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Angela F. Harper, Bartomeu Monserrat, Andrew J. Morris. 2022-06-21. Finite Temperature Effects on the X-ray Absorption Spectra of Crystalline Aluminas from First Principles. https://arxiv.org/abs/2206.10448

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