CaF2熔化温度的分子动力学模拟

利用壳层模型分子动力学方法,研究了高温高压条件下CaF2的熔化温度,同时计算了温度为300K、压强上升到100GPa时CaF2 的状态方程.研究中考虑了分子动力学模拟的过热熔化,通过晶体的现代熔化理论,对CaF2 的分子动力学模拟熔化温度进行了修正, 获得了高温高压下CaF2的熔化温度.因此,常压下壳层模型分子动力学方法为研究物质熔化提供了一个很好的方法.

Molecular Dynamics Simulations for Melting Temperatures of CaF2

The molecular dynamics method has been applied to simulate the melting temperatures of CaF_2 at elevated temperature and high pressure and to calculate the P~V equation of state of CaF_2 up to 100 GPa at 300 K. The interatomic potential was taken to be the sum of pairwise additive Coulomb, van der Waals attractions, and repulsive interactions. In addition, the shell model was used in molecular dynamics simulation. The pressure dependence of the melting temperature of CaF_2 was predicted up to 4 GPa. However, in order to account for the superheating melting of the molecular dynamic simulation, the simulated melting temperatures of CaF_2 were corrected by the modern theory of melting. Consequently, the melting temperatures of CaF_2 were accurately obtained at elevated temperature and high pressure. Therefore, it is shown that shell-model molecular dynamics simulation at constant pressure indeed provides a useful tool for studying the melting temperatures of other materials under high pressures.