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arXiv 1406.2659cond-mat.stat-mech
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用界面钉扎法计算晶体生长速率

Computing the crystal growth rate by the interface pinning method

Ulf R. Pedersen, Felix Hummel, Christoph Dellago

摘要:

晶体生长的一个基本参数是由过冷度和平均生长速度之间的比例给出的动力学系数。在这里,我们表明,这个系数可以计算在一个单一的平衡模拟使用的接口钉扎方法,两相配置是稳定的,通过添加一个弹簧般的偏置场耦合到一个序参数,区分两个阶段。晶体生长是Smoluchowski过程,因此晶体生长速率可以从序参量的终端指数弛豫计算。该方法进行了详细研究的Lennard-Jones模型。我们发现,动力学系数的比例作为温度的平方根的倒数沿熔化线的高温部分。用第一性原理计算了Na、Mg、Al、Si等元素的动力学系数,证明了该方法的实用性。它简要地讨论了如何一个广义的版本的方法是一种替代前向通量采样方法计算率沿轨迹的罕见事件。

英文摘要:

An essential parameter for crystal growth is the kinetic coefficient given by the proportionality between super-cooling and average growth velocity. Here we show that this coefficient can be computed in a single equilibrium simulation using the interface pinning method where two-phase configurations are stabilized by adding an spring-like bias field coupling to an order-parameter that discriminates between the two phases. Crystal growth is a Smoluchowski process and the crystal growth rate can therefore be computed from the terminal exponential relaxation of the order parameter. The approach is investigated in detail for the Lennard-Jones model. We find that the kinetic coefficient scales as the inverse square-root of temperature along the high temperature part of the melting line. The practical usability of the method is demonstrated by computing the kinetic coefficient of the elements Na, Mg, Al and Si from first principles. It is briefly discussed how a generalized version of the method is an alternative to forward flux sampling methods for computing rates along trajectories of rare events.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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