Ocádiz-Flores J A, Gheribi A E, Vlieland J, de Haas D, Dardenne K, Rothe J, Konings R J M, Smith A L
Delft University of Technology, Faculty of Applied Sciences, Radiation Science & Technology Department, Mekelweg 15, 2629 JB Delft, The Netherlands.
Phys Chem Chem Phys. 2021 May 14;23(18):11091-11103. doi: 10.1039/d1cp00566a. Epub 2021 May 4.
The short-range structures of LiF-ThF, NaF-AnF, KF-AnF, and Cs-AnF (An = Th, U), were probed using in situ high temperature Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. Signally, the EXAFS spectra of pure molten ThF and UF were measured for the first time. The data were interpreted with the aid of Molecular Dynamics (MD) and standard fitting of the EXAFS equation. As in related studies, a speciation distribution dominated by [AnF] (x = 7, 8, 9) coordination complexes was observed. The average coordination number was found to decrease with the increasing size of the alkali cation, and increase with AnF content. An average coordination number close to 6, which had not been detected before in melts of alkali actinide fluorides, was seen when CsF was used as solvent.
利用原位高温扩展X射线吸收精细结构（EXAFS）光谱对LiF-ThF、NaF-AnF、KF-AnF和Cs-AnF（An = Th、U）的短程结构进行了探测。值得注意的是，首次测量了纯熔融ThF和UF的EXAFS光谱。借助分子动力学（MD）和EXAFS方程的标准拟合对数据进行了解释。与相关研究一样，观察到以[AnF]（x = 7、8、9）配位络合物为主的物种分布。发现平均配位数随碱金属阳离子尺寸的增加而减小，随AnF含量的增加而增加。当使用CsF作为溶剂时，观察到平均配位数接近6，这在碱金属锕系氟化物熔体中以前未被检测到。
