Martínez-Haya B, Cuetos A, Lago S
Departamento de Ciencias Ambientales, Facultad de Ciencias Experimentales, Universidad Pablo de Olavide, Ctra. de Utrera Km 1, 41013 Seville, Spain.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 May;67(5 Pt 1):051201. doi: 10.1103/PhysRevE.67.051201. Epub 2003 May 19.
The Percus-Yevick equation for square-well spherocylinders has been numerically solved for some selected orientations following a methodology proposed previously for different fluids of elongated molecules. The equation is solved for particles of aspect ratios ranging from L/sigma=0.3 up to L/sigma=5.0, attractive range lambda/sigma=1.5, and packing fractions within eta=0.1-0.3. The resulting pair correlation functions are checked against isothermal-isobaric Monte Carlo simulations and good agreement is found for the short-range structure, at intermolecular distances within one molecular diameter sigma to contact for each of the selected orientations. At larger distances, the integral equation tends to overestimate the pair correlations. The results confirm the prediction of reference-system average Mayer-function perturbation theory for short aspect ratios, reaching the Onsager limit for the greater aspect ratios. Some instabilities of the solution for the longest models and higher densities are tentatively discussed in terms of their possible relation to frustration phenomena found in some polymer and complex systems.
对于方阱球柱体的珀库斯 - 耶维克方程，已按照先前针对不同细长分子流体提出的方法，对一些选定的取向进行了数值求解。该方程针对长径比范围从(L/\sigma = 0.3)到(L/\sigma = 5.0)、吸引范围(\lambda/\sigma = 1.5)以及堆积分数在(\eta = 0.1 - 0.3)内的粒子进行求解。将所得的对关联函数与等温等压蒙特卡罗模拟结果进行核对，发现在所选每个取向中，分子间距离在一个分子直径(\sigma)以内直至接触的短程结构方面，两者吻合良好。在更大距离处，积分方程往往会高估对关联。结果证实了参考系统平均迈耶函数微扰理论对于短长径比的预测，对于更大长径比则达到了昂萨格极限。对于最长模型和更高密度时解的一些不稳定性，初步从它们与某些聚合物和复杂系统中发现的受挫现象的可能关系方面进行了讨论。
