Reverse nonequilibrium molecular-dynamics calculation of the Soret coefficient in liquid benzene/cyclohexane mixtures.
Reverse nonequilibrium molecular-dynamics calculation of the Soret coefficient in liquid benzene/cyclohexane mixtures.
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DOI：
10.1063/1.2042427
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发表时间：
2005-09
期刊：
影响因子：
--
通讯作者：
Meimei Zhang;F. Müller-Plathe
中科院分区：
文献类型：
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作者：
Meimei Zhang;F. Müller-Plathe
本文采用反非平衡分子动力学方法来研究实际分子流体中的热扩散问题。采用全原子模型计算了苯/环己烷混合物的Soret系数。自相关函数表明摩尔分数梯度的收敛速度比温度梯度慢得多。与实验数据比较，结果表明Soret系数随摩尔分数的变化趋势相同。虽然索雷特系数的大小存在系统误差，但同时互扩散系数和热扩散系数的系统误差提供了一些解释；在不同力场参数下的计算表明了消除系统误差的可能性。测试了截止长度和扰动强度等算法变量的影响。此外，还观察到索雷特效应的温度依赖性，得出与以前研究相同的趋势。
Reverse nonequilibrium molecular dynamics is the method applied here for the investigation of thermal diffusion in realistic molecular fluids. The Soret coefficients of benzene/cyclohexane mixtures are calculated using an all-atom model. The autocorrelation functions indicate that the mole fraction gradient converges much slower than the temperature gradient. Compared to experimental data, the results show the same tendency of the Soret coefficient variation versus the mole fraction. Although a systematic error exists for the magnitude of the Soret coefficient, a meanwhile systematic error for both the mutual diffusion and thermal diffusion coefficients provides some explanation of it; and the calculation with different force field parameters indicates a possibility to annihilate the systematic error. The influences of algorithm variables such as cutoff lengths and perturbation intensities are tested. Furthermore the temperature dependence of the Soret effect is observed, yielding the same trend as previous studies.