The influence of potential softness on the transport coefficients of simple fluids.
The influence of potential softness on the transport coefficients of simple fluids.
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DOI：
10.1063/1.1931668
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发表时间：
2005-06
期刊：
影响因子：
--
通讯作者：
D. Heyes;A. Brańka
中科院分区：
文献类型：
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作者：
D. Heyes;A. Brańka
本研究探讨了相互作用软度对简单流体输运性质的影响。本文用分子动力学计算机模拟方法计算了软球流体的输运系数，其中粒子间的相互作用势为φ（r）= φ（rsigma）（-n），n在6 ~ 1152之间。自扩散系数D剪切粘度η（s）、体积粘度η（B）和热导率λ在宽的填充分数范围内计算。结果发现，Batschinski-Hildebrand表达式，其中D，eta（s）（-1），eta（B）（-1），和lambda（-1）被假定为有一个线性依赖于摩尔体积，代表的数据相当不错的所有n，虽然最不好的热导率。在外推时，这些量中的每一个都为零的密度随着相互作用的软度（或近似n（-1））而增加，这表明在小n极限下，有效硬球直径随着软度的增加而减小。这种处理导致简单的经验公式的密度和n上的有效硬球直径和填充分数（在中间范围内）和这些流体的四个传输系数的效果。
This study explores the effects of interaction softness on the transport properties of simple fluids. The transport coefficients of soft-sphere fluids in which the particles interact via the potential, phi(r)=epsilon(rsigma)(-n), with n in the range from 6 to 1152, have been calculated by molecular-dynamics computer simulation. The self-diffusion coefficient D shear viscosity eta(s), bulk viscosity eta(b), and thermal conductivity lambda were computed over a wide packing fraction range. It was found that the Batschinski-Hildebrand expressions, in which D, eta(s) (-1), eta(b) (-1), and lambda(-1) are assumed to have a linear dependence on the molar volume, represent the data quite well for all n, although least well for the thermal conductivity. The density for which, on extrapolation, each of these quantities is zero, increases with the softness of the interaction (or approximately n(-1)), suggesting that the effective hard-sphere diameter decreases with increasing softness in the small n limit. This treatment leads to simple empirical formulas for the effect of density and n on the effective hard-sphere diameter and packing fraction (in an intermediate range) and the four transport coefficients of these fluids.