非加和硬球混合物相共存的理论与计算机模拟研究

Theoretical and computer simulation study of phase coexistence of nonadditive hard-disk mixtures.

作者信息

Fiumara Giacomo, Pandaram Owen D, Pellicane Giuseppe, Saija Franz

机构信息

Department of Mathematics and Computer Science, University of Messina, Viale F. Stagno D'Alcontres 31, I-98166 Messina, Italy.

School of Chemistry and Physics, University of Kwazulu-Natal, Scottsville 3209, Pietermaritzburg, South Africa.

出版信息

J Chem Phys. 2014 Dec 7;141(21):214508. doi: 10.1063/1.4902440.

DOI:10.1063/1.4902440

PMID:25481153

Abstract

We have studied the equation of state (EOS) and the equilibrium behavior of a two-component mixture of equal-sized, nonadditive hard disks with an interspecies collision diameter that is larger than that of each component. For this purpose, we have calculated the fifth virial coefficient by evaluating numerically the irreducible cluster integrals by a Monte Carlo method. This information is used to calculate both the virial equation of state and an equation of state based on a resummation of the virial expansion. Then, the fluid-fluid phase coexistence boundaries are determined by integrating the EOS so as to obtain the free energy of the system. Canonical and Gibbs ensemble Monte Carlo simulations over a wide range of nonadditivity are also performed in order to provide a benchmark to the theoretical predictions.

摘要

我们研究了等尺寸、非加和性硬球二元混合物的状态方程（EOS）以及平衡行为，其中种间碰撞直径大于各组分的碰撞直径。为此，我们通过蒙特卡罗方法对不可约团簇积分进行数值评估，计算了第五维里系数。该信息用于计算维里状态方程以及基于维里展开重求和的状态方程。然后，通过对EOS进行积分以获得系统的自由能，从而确定流体 - 流体相共存边界。为了给理论预测提供基准，还在广泛的非加和性范围内进行了正则系综和吉布斯系综蒙特卡罗模拟。