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熔融NaF-AlF3-Al2O3-MF(M=Ca, Li, K)的微观性质及拉曼光谱的第一性原理分子动力学研究
Study on microscopic properties and Raman spectra of molten NaF-AlF3-Al2O3-MF (M=Ca, Li, K) using First-Principles molecular dynamics
【摘要】 本文利用第一性原理分子动力学结合Voronoi细分法,研究了NaF-AlF3-Al2O3-CaF2/LiF/KF体系的微观结构、自扩散系数、电子性质和拉曼光谱。结果表明,Na+、Ca2+、Li+和K+主要以游离态形式存在,Al3+、F-和O2-形成了络合离子团。Al-F络合离子团由[AlF6]3-、[AlF5]2-和[AlF4]-组成,Al-O-F络合离子团通过O2-替换Al-F络合离子团中的F-形成。Al-F和Al-O离子对的平均距离均为1.725?。在含KF体系中,Al-F离子对的配位数高于其它体系,而Al-O离子对的配位数低于其它体系。Na+、Ca2+、Li+和K+具有较强的扩散能力,而Al3+和O2-的扩散能力相对较弱,F-的扩散性略强于Al3+。在含LiF和KF的体系中,Al-F键表现出更高的稳定性,而Al-O键在含LiF的体系中更加稳定。
【Abstract】 In this paper, the microstructure, self-diffusion coefficient, electronic properties and Raman spectra of NaF-AlF3-Al2O3-CaF2/LiF/KF system were studied by First-Principles molecular dynamics combined with Voronoi tessellation method. The results show that Na+, Ca2+, Li+ and K+ mainly exist in free state. Al3+ ions form complex ion groups with F- and O2- ions. The Al-F complex ion groups are composed of [AlF6]3-, [AlF5]2- and [AlF4]-. The Al-O-F complex ion group is formed by replacing F- in the Al-F complex ion group with O2-. The average distance between Al-F and Al-O ion pairs is 1.725 ?. In the system containing KF, the coordination number of Al-F ion pair is higher than that of other systems, while the coordination number of Al-O ion pair is lower than that of other systems. Na+, Ca2+, Li+ and K+ have strong diffusion ability, while Al3+ and O2- have relatively weak diffusion ability, and F- has slightly stronger diffusion ability than Al3+. In the system containing LiF and KF, the Al-F bond is more stable, while the Al-O bond is more stable in the system containing LiF.
【Key words】 First-Principles molecular dynamics; NaF-AlF3-Al2O3-CaF2/LiF/KF; microstructure; diffusion coefficient; atomic charge; Raman spectrum;
- 【文献出处】 轻金属 ,Light Metals , 编辑部邮箱 ,2024年12期
- 【分类号】TF821;O657.37
- 【下载频次】86