Kazan Federal University, Kremlevskaya Street 18, 420000 Kazan, Russia.
J Chem Phys. 2014 Jan 14;140(2):024104. doi: 10.1063/1.4851438.
We present the statistical method as a direct extension of the mean first-passage time concept to the analysis of molecular dynamics simulation data of a phase transformation. According to the method, the mean first-passage time trajectories for the first (i = 1) as well as for the subsequent (i = 2, 3, 4,[ellipsis (horizontal)]) nucleation events should be extracted that allows one to calculate the time-dependent nucleation rate, the critical value of the order parameter (the critical size), the waiting times for the nucleation events, and the growth law of the nuclei - i.e., all the terms, which are usually necessary to characterize the overall transition kinetics. There are no restrictions in the application of the method by the specific thermodynamic regions; and the nucleation rate parameters are extracted according to their basic definitions. The method differs from the Wedekind-Bartell scheme and its modification [A. V. Mokshin and B. N. Galimzyanov, J. Phys. Chem. B 116, 11959 (2012)], where the passage-times for the first (largest) nucleus are evaluated only and where the average waiting time for the first nucleation event is accessible instead of the true steady-state nucleation time scale. We demonstrate an efficiency of the method by its application to the analysis of the vapor-to-liquid transition kinetics in water at the different temperatures. The nucleation rate/time characteristics and the droplet growth parameters are computed on the basis of the coarse-grained molecular dynamics simulation data.
我们提出了一种统计方法，将平均首次通过时间的概念直接扩展到相变的分子动力学模拟数据的分析中。根据该方法，应该提取第一个（i=1）以及随后的（i=2,3,4，[省略（水平）]）成核事件的平均首次通过时间轨迹，以便计算时变成核率、序参量的临界值（临界尺寸）、成核事件的等待时间以及核的生长规律-即通常需要描述整个转变动力学的所有术语。该方法在应用中不受特定热力学区域的限制；并且成核率参数是根据其基本定义提取的。该方法与 Wedekind-Bartell 方案及其修正[ A. V. Mokshin 和 B. N. Galimzyanov，J. Phys. Chem. B 116, 11959 (2012)]不同，后者仅评估了第一个（最大）核的通过时间，并且只能获得第一个成核事件的平均等待时间，而不是真实的稳态成核时间尺度。我们通过将其应用于分析不同温度下水的汽-液相变动力学，证明了该方法的效率。成核率/时间特性和液滴生长参数是基于粗粒度分子动力学模拟数据计算得出的。
