Comprehensive investigation about the second order term of thermodynamic perturbation expansion.
Comprehensive investigation about the second order term of thermodynamic perturbation expansion.
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DOI：
10.1063/1.3242801
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Shiqi Zhou;J. Solana
中科院分区：
文献类型：
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作者：
Shiqi Zhou;J. Solana
对硬球参考流体的热力学微扰展开中的二阶项进行了蒙特卡罗模拟。所研究的样品势涵盖了很宽的范围：从两种常用的势，即硬球加方阱势和硬核吸引Yukawa势，到两种排斥势，即硬球加方肩势和硬球加三角肩势;所研究的势范围也从极短的范围扩展到相当长的范围。所获得的模拟数据用于评估两种理论方法的性能，即，传统的宏观压缩性近似（MCA）和最近的耦合参数展开。广泛的比较表明，耦合参数展开提供了一个可靠的方法，精确计算的高温级数展开的二阶项，而广泛接受的MCA失败定量甚至定性的大多数情况下调查。
Monte Carlo simulations are carried out for the second order term in the thermodynamic perturbation expansion around a hard sphere reference fluid. The sample potentials considered cover a wide spectrum: From two frequently employed, namely hard sphere plus square well potential and hard core attractive Yukawa potential, to two kinds of repulsive potentials, namely hard sphere plus square shoulder potential and hard sphere plus triangle shoulder potential; the investigated potential range also extends from extremely short range to rather long range. The obtained simulation data are used to evaluate performance of two theoretical approaches, i.e., a traditional macroscopic compressibility approximation (MCA) and a recent coupling parameter expansion. Extensive comparison shows that the coupling parameter expansion provides a reliable method for accurately calculating the second order term of the high temperature series expansion, while the widely accepted MCA fails quantitatively or even qualitatively for most of the situations investigated.