Finite-temperature effects on the x-ray absorption spectra of crystalline alumina from first principles
Finite-temperature effects on the x-ray absorption spectra of crystalline alumina from first principles
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DOI：
10.1063/5.0146033
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发表时间：
2022-06
期刊：
影响因子：
1.6
通讯作者：
Angela F. Harper;B. Monserrat;A. J. Morris
中科院分区：
文献类型：
--
作者：
Angela F. Harper;B. Monserrat;A. J. Morris
通过在平面波密度泛函理论方法中加入声子辅助跃迁来计算x射线吸收光谱（XAS），我们得到了两个Al2O3晶体相在300 K下的Al K边XAS。300 K XAS重现了α-Al2O3的前边缘峰，这在近似的静态晶格水平上是不可见的。在300 K XAS下对γ-Al2O3相空间进行蒙特卡罗采样的构型正确地描述了三个实验峰中的两个。我们发现第二个峰出现在1s到混合s-p跃迁之间，并且在0 K XAS中不存在。这封信可以作为氧化铝晶体的Al k边XAS特征峰的电子起源的见解。
By including phonon-assisted transitions within plane-wave density functional theory methods for calculating the x-ray absorption spectrum (XAS), we obtain the Al K-edge XAS at 300 K for two crystalline 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. Configurations from Monte Carlo sampling of the γ-Al2O3 phase space at the 300 K XAS correctly describe 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 an insight into the electronic origins of the characteristic peaks in the Al K-edge XAS for alumina crystals.