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arXiv 1211.2196cond-mat.soft
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涨落在纳米级液滴热力学中作用的证据和表面张力计算中的意义

Evidence for the role of fluctuations in the thermodynamics of nanoscale drops and the implications in computations of the surface tension

Jose G. Sampayo, Alexandr Malijevsky, Erich A. Muller, E. de Miguel, G. Jackson

摘要:

采用分子动力学模拟方法,对Lennard-Jones颗粒的汽液界面进行了模拟。对于平面汽液界面的自由能的变化被捕获的平均相应的能量变化,领先的顺序的贡献。这与表面张力常用的机械(压力张量)途径一致。相比之下,对于液滴,人们发现与能量波动相关的大的二阶贡献。一阶项和二阶项的贡献相当,使小液滴的表面张力的力学关系无效。后者被认为是增加以上的平面值的滴半径的~8个粒子直径,随后由一个明显的弱最大值和缓慢衰减到平面极限,与一个小的负托尔曼长度一致。

英文摘要:

Test area deformations are used to analyse vapour-liquid interfaces of Lennard-Jones particles by molecular dynamics simulation. For planar vapour-liquid interfaces the change in free energy is captured by the average of the corresponding change in energy, the leading-order contribution. This is consistent with the commonly used mechanical (pressure tensor) route for the surface tension. By contrast for liquid drops one finds a large second-order contribution associated with fluctuations in energy. Both the first- and second-order terms make comparable contributions, invalidating the mechanical relation for the surface tension of small drops. The latter is seen to increase above the planar value for drop radii of ~8 particle diameters, followed by an apparent weak maximum and slow decay to the planar limit, consistent with a small negative Tolman length.

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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