Fantoni Riccardo, Gazzillo Domenico, Giacometti Achille
Istituto Nazionale per la Fisica della Materia and Dipartimento di Chimica Fisica, Università di Venezia, S. Marta DD 2137, I-30123 Venezia, Italy.
J Chem Phys. 2005 Jan 15;122(3):34901. doi: 10.1063/1.1831275.
We study the polydisperse Baxter model of sticky hard spheres (SHS) in the modified mean spherical approximation (mMSA). This closure is known to be the zero-order approximation C0 of the Percus-Yevick closure in a density expansion. The simplicity of the closure allows a full analytical study of the model. In particular we study stability boundaries, the percolation threshold, and the gas-liquid coexistence curves. Various possible subcases of the model are treated in details. Although the detailed behavior depends upon the particularly chosen case, we find that, in general, polydispersity inhibits instabilities, increases the extent of the nonpercolating phase, and diminishes the size of the gas-liquid coexistence region. We also consider the first-order improvement of the mMSA (C0) closure (C1) and compare the percolation and gas-liquid boundaries for the one-component system with recent Monte Carlo simulations. Our results provide a qualitative understanding of the effect of polydispersity on SHS models and are expected to shed new light on the applicability of SHS models for colloidal mixtures.
我们在修正平均球近似（mMSA）中研究粘性硬球（SHS）的多分散 Baxter 模型。已知这种封闭近似是 Percus - Yevick 封闭近似在密度展开中的零阶近似 C0。该封闭近似的简单性使得能够对模型进行全面的解析研究。特别地，我们研究稳定性边界、渗流阈值和气液共存曲线。详细讨论了模型的各种可能子情况。尽管详细行为取决于具体选择的情况，但我们发现，一般而言，多分散性会抑制不稳定性，增加非渗流相的范围，并减小气液共存区域的大小。我们还考虑了 mMSA（C0）封闭近似的一阶改进（C1），并将单组分系统的渗流和气液边界与最近的蒙特卡罗模拟结果进行比较。我们的结果为多分散性对 SHS 模型的影响提供了定性理解，有望为 SHS 模型在胶体混合物中的适用性提供新的见解。
