多形性相变的分子动力学模拟

Molecular Dynamics Simulation of Polymorphous Transitions

Beijing Institute of Applied Physics and Computational Mathematics, Beijing 100088, China

摘要: 本文利用分子动力学方法研究了KCl晶体在＝0时的温度相变。面心立方（fcc）和体心立方（bcc）两种结构的径向分布函数随温度的变化的情况说明，在高压下，发生着bcc结构相fcc结构的转变，bcc结构是不稳定的。为了选取合理的势参数，利用了分子动力学程序在T＝0时的性质，计算了NaCl和KCl晶体的零温状态方程，研究了它们在压力作用下发生的多形性相变。计算表明，NaCl和KCl晶体将分别于18.8 GPa和5.9 GPa发生从fcc到bcc的多形性相变，这些值相当接近实验结果。着说明本文选用的势参数势有一定精度的。
- 多形性相变 /
- 分子动力学 /
- 高温高压
Abstract: In this paper, temperature-induced polymorphous transitions for KCl and NaCl crystals at ＝0 are investigated using a molecular dynamics method. The change of the radial distribution function with temperature indicates that there occurs the structural transition from bcc to fcc. In order to choose potential parameters, we calculated the equations of state for KCl and NaCl at 0 K and studied pressure-induced polymorphous transitions from fcc to bcc. The transition pressures for NaCl and KCl are 18.8 GPa and 5.9 GPa respectively, which are in agreement with the experimental results so that those potential parameters seem resonable.
- polymorphic transition /
- molecular dynamics /
- high temperature and high pressure