Application of integral equation theories to predict the structure of diatomic fluids
Application of integral equation theories to predict the structure of diatomic fluids
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应用积分方程理论预测双原子流体的结构
DOI：
10.1063/1.469468
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发表时间：
1995
影响因子：
4.4
通讯作者：
D. Blankschtein
中科院分区：
文献类型：
--
作者：
L. Lue;D. Blankschtein
我们比较了位-位Ornstein-Zernike方程和Elderler-Silbey-Ladanyi方程预测流体结构的能力：（i）由均质双原子Lennard-Jones分子组成的流体，和（ii）由非极性或极性异源双原子Lennard-Jones分子组成的流体。在（i）中，我们用Percus-Yevick（PY）闭包求解了位-位Ornstein-Zernike（SSOZ）方程，用超网链（HNC）闭包求解了Buller-Silbey-Ladanyi（CSL）方程，以预测不同键长、流体密度和温度下的各种对相关函数。在一般情况下，我们发现，CSL方程变得更准确，当与计算机模拟结果相比，作为键长的增加或密度降低，与温度没有显着的影响。事实上，在低于临界密度的密度下，CSL方程的流体结构预测被发现比SSOZ方程更接近于计算机模拟结果。我们还提出了一种在CSL方程的背景下计算低阶密度桥函数的一般方法。在均质双原子分子的情况下，零阶桥函数B（0），被发现对CSL方程的对关联函数预测的影响很小。然而，添加一阶桥函数B（1）会显著改善这些预测。在一般情况下，CSL方程的准确性，包括各种桥函数的校正，被发现增加的键长增加或密度降低，类似于我们发现时，HNC封闭（其中桥函数设置为零）被使用。最后，在（ii）中，我们发现，对于非极性的异质双原子流体，CSL方程，与HNC，HNC+B（0），和HNC+B（1）封闭，在预测较大的相互作用网站之间的相关函数表现得很好。对于极性异质双原子流体，我们发现CSL方程似乎提供了一个改进的SSOZ方程。同样，CSL方程为较大相互作用位点之间的相关函数提供了更好的预测。© 1995年美国物理研究所。
We compare the capabilities of the site-site Ornstein-Zernike equation and the Chandler-Silbey-Ladanyi equations to predict the fluid structure for: (i) fluids composed of homonuclear diatomic Lennard‐Jones molecules, and (ii) fluids composed of nonpolar or polar heteronuclear diatomic Lennard‐Jones molecules. In (i), we solve the site-site Ornstein-Zernike (SSOZ) equation with the Percus-Yevick (PY) closure, and the Chandler-Silbey-Ladanyi (CSL) equations with the hypernetted‐chain (HNC) closure to predict the various pair correlation functions at various bond lengths, fluid densities, and temperatures. In general, we find that the CSL equations become more accurate, when compared with computer simulation results, as the bond length increases or as the density decreases, with temperature having no significant effect. In fact, at densities below the critical density, the fluid structure predictions of the CSL equations are found to be in closer agreement with the computer simulation results than those of the SSOZ equation. We also present a general method for computing the low‐order density bridge functions in the context of the CSL equations. In the case of homonuclear diatomic molecules, the zeroth‐order bridge functions, B(0), are found to have little effect on the pair correlation function predictions of the CSL equations. However, the addition of the first‐order bridge functions, B(1), results in a significant improvement of these predictions. In general, the accuracy of the CSL equations, including the various bridge function corrections, is found to increase as the bond length increases or as the density decreases, similar to what we found when the HNC closure (in which the bridge functions are set equal to zero) was used. Finally, in (ii), we find that for nonpolar heteronuclear diatomic fluids, the CSL equations, with the HNC, HNC+B(0), and HNC+B(1) closures, perform very well in predicting the correlation functions between the larger interactions sites. For polar heteronuclear diatomic fluids, we find that the CSL equations seem to offer an improvement over the SSOZ equation. Once again, the CSL equations provide better predictions for the correlation function between the larger interaction sites. © 1995 American Institute of Physics.