Numerical calculation of the rate of crystal nucleation in a Lennard‐Jones system at moderate undercooling
Numerical calculation of the rate of crystal nucleation in a Lennard‐Jones system at moderate undercooling
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DOI：
10.1063/1.471721
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发表时间：
1996-06
影响因子：
4.4
通讯作者：
P. T. Wolde;M. Ruiz-Montero;D. Frenkel
中科院分区：
文献类型：
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作者：
P. T. Wolde;M. Ruiz-Montero;D. Frenkel
我们报道了一项在中等过冷度下对Lennard - Jones体系中均匀晶体成核速率和晶核结构的计算机模拟研究。成核势垒的高度已通过伞形采样确定，而势垒跨越速率则是通过分子动力学模拟计算的。模拟清楚地表明，势垒跨越是一个扩散过程。然而，发现成核速率中的动力学前置因子比经典成核理论所预测的大约高两个数量级。势垒的高度与理论预测吻合良好。尽管Lennard - Jones体系在熔点线以下具有稳定的面心立方（fcc）相，但发现亚临界晶核主要是体心立方（bcc）有序的。当它们生长到临界尺寸时，其核心变得更具面心立方有序性。然而，临界和超临界晶核在界面处保留了高度的体心立方有序性。（最后一个“F...”不太明确是什么意思，如果还有后续内容，请补充完整以便更准确地翻译）
We report a computer‐simulation study of the rate of homogeneous crystal nucleation and the structure of crystal nuclei in a Lennard‐Jones system at moderate undercooling. The height of the nucleation barrier has been determined using umbrella sampling, whereas the barrier crossing rate is calculated using molecular dynamics simulation. The simulations clearly show that the barrier crossing is a diffusive process. Nevertheless, the kinetic prefactor in the nucleation rate is found to be some two orders of magnitude larger than predicted by classical nucleation theory. The height of the barrier is in good agreement with the theoretical prediction. Although the Lennard‐Jones system has a stable face‐centered cubic (fcc) phase below the melting line, the precritical nuclei are found to be mainly body‐centered cubic (bcc) ordered. As they grow to their critical size, they become more fcc ordered in the core. However, the critical and postcritical nuclei retain a high degree of bcc ordering in the interface. F...