二元Lennard-Jones液体的相分离过程及其扩散性质的分子动力学研究

采用分子动力学(MD)模拟方法，研究了二元体系中相分离过程、粒子的扩散系数以及相分离域尺寸大小随温度的变化规律.发现，相分离域随温度的生长过程可以分为两个阶段，分别是温度比较高的快速生长阶段和低温时的稳定生长阶段；相分离体系中系统的扩散激活能不是常数，而是一个随温度变化的函数，并且当温度高于60 K时，满足关系式E(T)=a+bT^c.讨论了组元尺寸的变化对相分离过程的影响.结果表明，随两组元中某一组元 关键词： 相分离 扩散 分子动力学模拟

Molecular dynamics study of the phase separation and diffusion in Lennard-Jones binary liquid

Molecular dynamics (MD) simulation is performed to study the diffusion and phase separation process in binary Lennard-Jones (LJ) liquid. It is found that the growth of phase separation with temperature can be divided into two stages. The first is the fast-growth at high temperatures and the second is the steady-growth at low temperatures. Diffusion activation energy in the phase separation system is not a constant, but a function of temperature and follows the relation of E=a+bT^c. The influence of the sizes of the components on the phase separation is also discussed. The results shows that the diffusivity increases when the component size decreases. This facilitates the phase separation.