Phase field theory of crystal nucleation in hard sphere liquid
Phase field theory of crystal nucleation in hard sphere liquid
复制标题
硬球液体中晶体成核的相场理论
DOI：
10.1063/1.1618213
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发表时间：
2003
影响因子：
4.4
通讯作者：
B. Kvamme
中科院分区：
文献类型：
--
作者：
L. Gránásy;T. Pusztai;Z. Jurek;M. Conti;B. Kvamme
在L. Granasy， T. Borzsonyi和T. Pusztai中描述了晶体成核的相场理论。Rev. Lett. 88, 206105（2002）适用于硬球液体的成核。使用了分子动力学的精确热力学。根据单重态密度峰高度的界面变化来计算相场的界面厚度。将模型参数固定在平衡状态，以便从分子动力学中恢复（111）、（110）和（100）界面的自由能和厚度。在没有可调参数的情况下预测的密度分布与模拟得到的过滤密度吻合良好。假设球对称，我们在没有可调参数的情况下计算成核势垒的高度和托尔曼长度。用（111）和（110）界面性质计算得到的势垒高度与蒙特卡罗结果基本一致，而用平均界面性质计算得到的势垒高度与蒙特卡罗结果非常接近。相比之下，经典的锐界面模型大大低估了成核势垒的高度。我们发现托尔曼长度对于小的星团是正的，并且随着星团大小的增加而减小，这一趋势与计算机模拟结果一致。
The phase field theory of crystal nucleation described in L. Granasy, T. Borzsonyi, and T. Pusztai, Phys. Rev. Lett. 88, 206105 (2002) is applied for nucleation in hard-sphere liquids. The exact thermodynamics from molecular dynamics is used. The interface thickness for phase field is evaluated from the cross-interfacial variation of the height of the singlet density peaks. The model parameters are fixed in equilibrium so that the free energy and thickness of the (111), (110), and (100) interfaces from molecular dynamics are recovered. The density profiles predicted without adjustable parameters are in a good agreement with the filtered densities from the simulations. Assuming spherical symmetry, we evaluate the height of the nucleation barrier and the Tolman length without adjustable parameters. The barrier heights calculated with the properties of the (111) and (110) interfaces envelope the Monte Carlo results, while those obtained with the average interface properties fall very close to the exact values. In contrast, the classical sharp interface model considerably underestimates the height of the nucleation barrier. We find that the Tolman length is positive for small clusters and decreases with increasing size, a trend consistent with computer simulations.