Homogeneous and heterogeneous nucleation of Lennard-Jones liquids.
Homogeneous and heterogeneous nucleation of Lennard-Jones liquids.
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DOI：
10.1103/physreve.76.031604
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发表时间：
2007-06
期刊：
影响因子：
--
通讯作者：
Hui Wang;H. Gould;W. Klein
中科院分区：
文献类型：
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作者：
Hui Wang;H. Gould;W. Klein
采用伞形取样法研究了Lennard-Jones液体的均质和非均质成核。形成成核液滴的自由能成本被确定为淬火深度的函数，并且使用干预技术验证液滴的鞍点性质。在一定的温度范围内发现了成核液滴的结构和对称性。我们发现，深淬火的成核液滴变得更加各向异性和扩散，没有明确的核心或表面。成核液滴的环境形成随机堆叠的六边形平面。这种行为是一致的亚稳核的解释。当杂质的晶格间距等于平衡晶相的晶格间距时，异质形核的自由能垒最小。如果杂质的晶格间距不同，则晶体生长到块体中而不是润湿杂质。
The homogeneous and heterogeneous nucleation of a Lennard-Jones liquid is investigated using the umbrella sampling method. The free energy cost of forming a nucleating droplet is determined as a function of the quench depth, and the saddle point nature of the droplets is verified using an intervention technique. The structure and symmetry of the nucleating droplets are found for a range of temperatures. We find that for deep quenches the nucleating droplets become more anisotropic and diffuse with no well-defined core or surface. The environment of the nucleating droplets forms randomly stacked hexagonal planes. This behavior is consistent with a spinodal nucleation interpretation. We also find that the free energy barrier for heterogeneous nucleation is a minimum when the lattice spacing of the impurity equals the lattice spacing of the equilibrium crystalline phase. If the lattice spacing of the impurity is different, the crystal grows into the bulk instead of wetting the impurity.