熔融NaCaF_3、Na_2CaF_4和Na_3CaF_5的分子动力学模拟

Molecular Dynamics Simulations of Molten Salt Solutions NaCaF_3, Na_2CaF_4 and Na_3CaF_5

通过分子动力学模拟，研究了熔盐溶液NaCaF3、Na2CaF4和Na4CaF5体系，模拟表明，三种二元混合系的径向分布函数十分接近．由模拟所得到的摩尔混合焓很好地与实验值一致．混合焓与Na＋离子势阱深度之间表现出很好的线性关系．模拟表明，在Na2CaF4体系中，即NaF－CaF2二元系处于低共熔混合组分比NaF：CaF2＝2：1时，Na＋，Ca2＋和F－离子的自扩散系数出现很大的反常．

The molten salt solutions NaCaF3, NA2CaF4 and Na3CaF5 have been studied by molecular dynaAncs simulation. The siumlations show that the radial distIibution functions in the three mixture systems are very much closed to each other. The molar ndking enthalpy obtained from the simulations reproduced the experimental value very well. The relation between the dring enthalpy and the depth of Na+ cation's potential well have been found to bd nearly linear. The selfdimision coefficients of Na+ ) Ca2+ and F- ions in the Na2CaF4 system, which is an eutectic Anxture with the comPonent ratio NaF:CaF2=2:1, appeared anomaly large.