Eskandari Nasrabad Afshin, Laghaei Rozita
Department of Chemistry, McGill University, 801 Sherbrooke West, Montreal, Quebec H3A 2K6, Canada.
J Chem Phys. 2006 Aug 28;125(8):084510. doi: 10.1063/1.2338310.
A quantum mechanical derived ab initio interaction potential for the argon dimer was tested in molecular simulations to reproduce the thermophysical properties of the vapor-liquid phase equilibria using the Gibbs ensemble Monte Carlo simulations as well as the liquid and supercritical equation of state using the NVT Monte Carlo simulations. The ab initio interaction potential was taken from the literature. A recently developed theory [R. Laghaei et al., J. Chem. Phys. 124, 154502 (2006)] was used to compute the effective diameters of argon in fluid phases and the results were subsequently applied in the generic van der Waals theory to compute the free volume of argon. The calculated densities of the coexisting phases, the vapor pressure, and the equation of state show excellent agreement with experimental values. The effective diameters and free volumes of argon are given over a wide range of densities and temperatures. An empirical formula was used to fit the effective diameters as a function of density and temperature. The computed free volume will be used in future investigations to calculate the transport properties of argon.
在分子模拟中测试了一种从量子力学推导得到的氩二聚体的从头算相互作用势,以使用吉布斯系综蒙特卡罗模拟重现气液相平衡的热物理性质,并使用NVT蒙特卡罗模拟重现液体和超临界状态方程。从头算相互作用势取自文献。利用最近发展的理论[R. Laghaei等人,《化学物理杂志》124, 154502 (2006)]计算了氩在流体相中的有效直径,随后将结果应用于通用范德华理论以计算氩的自由体积。计算得到的共存相密度、蒸气压和状态方程与实验值显示出极好的一致性。给出了在广泛的密度和温度范围内氩的有效直径和自由体积。使用一个经验公式将有效直径拟合为密度和温度的函数。计算得到的自由体积将用于未来的研究中以计算氩的输运性质。