A molecular dynamics study of surface melting
A molecular dynamics study of surface melting
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DOI：
10.1088/0022-3719/11/13/021
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发表时间：
1978-07
期刊：
影响因子：
--
通讯作者：
J. Broughton;L. V. Woodcock
中科院分区：
文献类型：
--
作者：
J. Broughton;L. V. Woodcock
用分子动力学方法研究了Lennard-Jones晶体1，0，0面沿着晶体-蒸气共存线的表面预熔效应。最外层的晶体层在0.48-0.50 Ω/K的狭窄温度范围内变成准流体，这可以通过表面平面中扩散率的快速增加以及异常一级转变行为的平衡特性的不连续性来证明。第二层和第三层分别在0.60-0.62 Ω/k和0.67-0.69 Ω/k下观察到类似的熔化，后者接近三相点温度。系统的几个属性的报告和讨论的背景下，熔化模型和可用的技术，表明如何表面熔化可能被检测到的LEED实验。据证实，表面熔化应发生所有单组分晶体-蒸汽界面的类似机制，在这里报道。一个简单的经验熔化规则的建议：每一层熔化时，该层中的每个原子的动能与势能的比例变得等于相同的比例，为大块晶体在其熔点。
The 1,0,0 face of a Lennard-Jones crystal has been examined for surface premelting effects along the crystal-vapour coexistence line by the method of molecular dynamics. The outermost crystal layer becomes quasi-fluid within the narrow temperature range 0.48-0.50 epsilon /k, as evidenced by a rapid increase in diffusivity in the surface plane, and by discontinuities in equilibrium properties characteristic of anomalous first-order transition behaviour. Similar melting is observed for the second and third layers at 0.60-0.62 epsilon /k and 0.67-0.69 epsilon /k respectively, the latter being close to the triple-point temperature. Several properties of the system are reported and discussed in the context of both melting models and available techniques, indicating how surface melting might be detected by LEED experiments. It is conjectured that surface melting should occur for all single-component crystal-vapour interfaces by a similar mechanism to that reported here. A simple empirical melting rule is suggested: Each layer melts when the ratio of kinetic to potential energy per atom in that layer becomes equal to the same ratio as for the bulk crystal at its melting point.