Confinement, entropy, and single-particle dynamics of equilibrium hard-sphere mixtures
Confinement, entropy, and single-particle dynamics of equilibrium hard-sphere mixtures
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DOI：
10.1063/1.2795699
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发表时间：
2007-10-21
影响因子：
4.4
通讯作者：
Truskett, Thomas M.
中科院分区：
文献类型：
--
作者：
Mittal, Jeetain;Shen, Vincent K.;Truskett, Thomas M.
我们使用不连续的分子动力学和巨正则过渡矩阵蒙特卡罗模拟，探讨如何限制平行硬壁之间的修改包装分数，自扩散率，偏摩尔过剩熵，和总过剩熵的二元硬球混合物之间的关系。为了实现这一点，我们引入了一个有效的算法来计算偏摩尔过量熵的过渡矩阵蒙特卡罗模拟数据。我们发现，物种依赖的自扩散系数的封闭流体是非常相似的散装混合物，如果在相同的，适当定义的，包装分数到中间值相比，但随后偏离负面的散装行为在较高的包装分数。另一方面，自扩散率和偏摩尔过剩熵（或总过剩熵）之间的关系，在散装流体中观察到的约束下保存，即使在相对较高的包装分数和不同的混合物组合物。这表明，过剩熵，计算从经典的密度泛函理论的非均匀流体，可以用来预测一些非平凡的流体混合物在密闭环境中的动力学行为。(C)2007年，美国物理学会。
We use discontinuous molecular dynamics and grand-canonical transition-matrix Monte Carlo simulations to explore how confinement between parallel hard walls modifies the relationships between packing fraction, self-diffusivity, partial molar excess entropy, and total excess entropy for binary hard-sphere mixtures. To accomplish this, we introduce an efficient algorithm to calculate partial molar excess entropies from the transition-matrix Monte Carlo simulation data. We find that the species-dependent self-diffusivities of confined fluids are very similar to those of the bulk mixture if compared at the same, appropriately defined, packing fraction up to intermediate values, but then deviate negatively from the bulk behavior at higher packing fractions. On the other hand, the relationships between self-diffusivity and partial molar excess entropy (or total excess entropy) observed in the bulk fluid are preserved under confinement even at relatively high packing fractions and for different mixture compositions. This suggests that the excess entropy, calculable from classical density functional theories of inhomogeneous fluids, can be used to predict some of the nontrivial dynamical behaviors of fluid mixtures in confined environments. (C) 2007 American Institute of Physics.