Investigation of the local structure of molten ThF4-LiF and ThF4-LiF-BeF2 mixtures by high-temperature X-ray absorption spectroscopy and molecular-dynamics simulation.
Investigation of the local structure of molten ThF4-LiF and ThF4-LiF-BeF2 mixtures by high-temperature X-ray absorption spectroscopy and molecular-dynamics simulation.
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DOI：
10.1107/s1600577519009718
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发表时间：
2019-08
影响因子：
2.5
通讯作者：
Jian Sun;Xiaojing Guo;Jing Zhou;J. Dai;Sanzhao Song;Hong-liang Bao;Jian Lin;Haisheng Yu;
中科院分区：
文献类型：
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作者：
Jian Sun;Xiaojing Guo;Jing Zhou;J. Dai;Sanzhao Song;Hong-liang Bao;Jian Lin;Haisheng Yu;
采用原位高温X射线吸收精细结构谱（XAFS）结合分子动力学（MD）模拟，系统研究了ThF 4-LiF和ThF 4-LiF-BeF 2熔盐的微观结构.结果表明，在熔融态下，ThF 4-LiF-BeF 2盐中钍离子的局域结构比ThF 4-LiF盐中的更无序，这意味着在Be离子存在下，Th和F离子的交换更频繁。通过实验和理论XAFS分析，我们强调了中程有序配位壳层（如Th-F2 nd和Th-Th）的结构，它们在输运性质中起着重要作用。使用MD模拟，评估熔融ThF 4-LiF和ThF 4-LiF-BeF 2混合物中的结合性质，证实了上述结论。据我们所知，这项研究是第一个系统的研究ThF 4-LiF-BeF 2熔盐通过定量原位XAFS分析和MD模拟。
The microscopic structures of ThF4-LiF and ThF4-LiF-BeF2 molten salts have been systematically investigated by in situ high-temperature X-ray absorption fine-structure (XAFS) spectroscopy combined with molecular-dynamics (MD) simulations. The results reveal that the local structure of thorium ions was much more disordered in the molten state of the ThF4-LiF-BeF2 salt than that in ThF4-LiF, implying that the Th and F ions were exchanged more frequently in the presence of Be ions. The structures of medium-range-ordered coordination shells (such as Th-F2nd and Th-Th) have been emphasized by experimental and theoretical XAFS analysis, and they play a significant role in transport properties. Using MD simulations, the bonding properties in the molten ThF4-LiF and ThF4-LiF-BeF2 mixtures were evaluated, confirming the above conclusion. This research is, to the best of our knowledge, the first systematic study on the ThF4-LiF-BeF2 molten salt via quantitative in situ XAFS analysis and MD simulations.