Crystal nucleation of hard spheres using molecular dynamics, umbrella sampling, and forward flux sampling: A comparison of simulation techniques
Crystal nucleation of hard spheres using molecular dynamics, umbrella sampling, and forward flux sampling: A comparison of simulation techniques
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DOI：
10.1063/1.3506838
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发表时间：
2010-12-28
影响因子：
4.4
通讯作者：
Dijkstra, M.
中科院分区：
文献类型：
--
作者：
Filion, L.;Hermes, M.;Dijkstra, M.
在过去的几年里，已经引入了几种模拟方法来研究罕见的事件，如成核。本文利用分子动力学、正向通量采样和Bennett-Chandler理论三种数值方法研究了硬球的晶体成核速率，其中成核势垒由伞形采样模拟来确定。所得到的成核率与Harland和van Megen的实验值进行了比较。Rev.E 55,3054(1997)]，Sinn等人。[程序.胶体聚合体SCI。[118,266(2001)]，Schatzel and Ackerson[Phys.修订版E 48,3766(1993)]，以及单分散和5%多分散硬球Auer和Frenkel的预测率[自然409,1020(2001)]。当以长时间扩散系数为单位考察这些速率时，我们发现所有理论预测的形核速率之间是一致的，然而，在低过饱和度时，实验结果表现出明显不同的行为。此外，我们还研究了在分子动力学、正向通量采样和伞形采样模拟中出现的前临界核。原子核的结构似乎与模拟方法无关，并且在所有情况下，原子核包含的面中心立方体有序粒子平均比六方密排有序粒子多得多。(C)2010年美国物理研究所。[DOI：10.1063/1.3506838]
Over the last number of years several simulation methods have been introduced to study rare events such as nucleation. In this paper we examine the crystal nucleation rate of hard spheres using three such numerical techniques: molecular dynamics, forward flux sampling, and a Bennett-Chandler-type theory where the nucleation barrier is determined using umbrella sampling simulations. The resulting nucleation rates are compared with the experimental rates of Harland and van Megen [Phys. Rev. E 55, 3054 (1997)], Sinn et al. [Prog. Colloid Polym. Sci. 118, 266 (2001)], Schatzel and Ackerson [Phys. Rev. E 48, 3766 (1993)], and the predicted rates for monodisperse and 5% polydisperse hard spheres of Auer and Frenkel [Nature 409, 1020 (2001)]. When the rates are examined in units of the long-time diffusion coefficient, we find agreement between all the theoretically predicted nucleation rates, however, the experimental results display a markedly different behavior for low supersaturation. Additionally, we examined the precritical nuclei arising in the molecular dynamics, forward flux sampling, and umbrella sampling simulations. The structure of the nuclei appears independent of the simulation method, and in all cases, the nuclei contains on average significantly more face-centered-cubic ordered particles than hexagonal-close-packed ordered particles. (C) 2010 American Institute of Physics. [doi:10.1063/1.3506838]