Mirzaeinia Ali, Feyzi Farzaneh
Thermodynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran.
J Chem Phys. 2020 Apr 7;152(13):134502. doi: 10.1063/1.5134511.
In the framework of thermodynamic perturbation theory (TPT), a new perturbed-chain equation of state (EOS) is presented for a fully flexible Lennard-Jones (LJ) chain system. The EOS is the sum of repulsive and perturbation contributions. The reference term of the EOS is derived based on first- and second-order TPT of Wertheim for the chains interacting with each other through the Weeks-Chandler-Anderson potential model. In order to derive the perturbation term, we have used the radial distribution function of the hard-chain system with a chain range of m = 2-10 and packing fraction range of η = 0.10-0.72, which cover the entire density range from vapor to solid phases. The performance of the EOS is tested against simulation data of the compressibility factor, residual internal energy, and phase equilibrium. A close agreement was observed across all cases. The EOS has three pure component parameters and is able to describe the global vapor-liquid-solid phase diagram of the LJ chain.
在热力学微扰理论（TPT）的框架下，针对完全柔性的 Lennard-Jones（LJ）链系统提出了一种新的微扰链状态方程（EOS）。该状态方程是排斥贡献和微扰贡献之和。状态方程的参考项是基于 Wertheim 的一阶和二阶 TPT 推导得出的，用于描述通过 Weeks-Chandler-Anderson 势模型相互作用的链。为了推导微扰项，我们使用了链长范围为 m = 2 - 10 且堆积分数范围为 η = 0.10 - 0.72 的硬链系统的径向分布函数，该范围涵盖了从气相到固相的整个密度范围。通过压缩因子、剩余内能和相平衡的模拟数据对该状态方程的性能进行了测试。在所有情况下都观察到了密切的一致性。该状态方程有三个纯组分参数，能够描述 LJ 链的全局气-液-固相图。
