Department für Materialwissenschaften und Prozesstechnik, Universität für Bodenkultur, Muthgasse 107, A-1190 Wien, Austria.
J Chem Phys. 2013 Nov 14;139(18):184902. doi: 10.1063/1.4827936.
Simple model systems with short-range attractive potentials have turned out to play a crucial role in determining theoretically the phase behavior of proteins or colloids. However, as pointed out by D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)], one of these widely used model potentials, namely, the attractive hard-core Yukawa potential, shows an unphysical behavior when one approaches its sticky limit, since the second virial coefficient is diverging. However, it is exactly this second virial coefficient that is typically used to depict the experimental phase diagram for a large variety of complex fluids and that, in addition, plays an important role in the Noro-Frenkel scaling law [J. Chem. Phys. 113, 2941 (2000)], which is thus not applicable to the Yukawa fluid. To overcome this deficiency of the attractive Yukawa potential, D. Gazzillo has proposed the so-called modified hard-core attractive Yukawa fluid, which allows one to correctly obtain the second and third virial coefficients of adhesive hard-spheres starting from a system with an attractive logarithmic Yukawa-like interaction. In this work we present liquid-vapor coexistence curves for this system and investigate its behavior close to the sticky limit. Results have been obtained with the self-consistent Ornstein-Zernike approximation (SCOZA) for values of the reduced inverse screening length parameter up to 18. The accuracy of SCOZA has been assessed by comparison with Monte Carlo simulations.
具有短程吸引力势的简单模型系统在从理论上确定蛋白质或胶体的相行为方面发挥了至关重要的作用。然而，正如 D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)] 所指出的，这些广泛使用的模型势之一，即有吸引力的硬球 Yukawa 势，在接近其粘性极限时表现出非物理行为，因为第二维里系数是发散的。然而，正是这个第二维里系数通常用于描绘各种复杂流体的实验相图，此外，它在 Noro-Frenkel 标度律 [J. Chem. Phys. 113, 2941 (2000)] 中起着重要作用，因此不适用于 Yukawa 流体。为了克服有吸引力的 Yukawa 势的这一缺陷，D. Gazzillo 提出了所谓的改进的硬球有吸引力的 Yukawa 流体，它允许从具有吸引力的对数 Yukawa 型相互作用的系统中正确获得粘性硬球的第二和第三维里系数。在这项工作中，我们提出了该系统的液-气相共存曲线，并研究了其在接近粘性极限时的行为。使用自洽的 Ornstein-Zernike 逼近（SCOZA）获得了直至 18 的约化反向屏蔽长度参数的结果。通过与蒙特卡罗模拟的比较评估了 SCOZA 的准确性。
