We study the gas-liquid phase diagram and the crossover behavior of a simple model of ionic fluid: an equimolar binary mixture of equisized hard spheres interacting through screened Coulomb potentials which are repulsive between particles of the same species and attractive between particles of different species. Using our previous results, we obtain explicit expressions for the relevant coefficients of the effective $φ^{4}$ Ginzburg-Landau Hamiltonian in a one-loop approximation. Within the framework of this approximation, we calculate the critical parameters and gas-liquid coexistence curves for different values of the dimensionless inverse screening length $z$. The critical temperature scaled by the Yukawa potential contact value as well as the critical packing fraction rapidly decrease with an increase of the interaction range and then for $z<0.05$ slowly approach the values found for a purely ionic model, i.e., a restricted primitive model (RPM). The both trends are qualitatively consistent with the results of Monte Carlo simulations. We find that gas-liquid coexistence region reduces with an increase of $z$ and completely vanishes at $z\simeq 2.781$. This qualitatively agrees with the results of Monte Carlo simulations indicating a stable gas-liquid coexistence for $z\leq 4$. It is also shown that an increase in the interaction range from the one typical of simple fluids to the one typical of ionic fluids leads to a decrease of the crossover temperature. For $z\simeq 0.01$, the crossover temperature is the same as for the RPM. For $z\simeq 2.781$, our results indicate a tricritical point.
我们模型带电胶体悬浮液使用泡沫的类比。我们研究了这些系统的固体-固体相变作为粒子体积分数和离子强度的函数。屏蔽库仑相互作用被每个粒子周围的Voronoi细胞壁之间的相互作用所取代。我们拟合表面电荷以再现Sirota等人研究的带电悬浮液的相图[Phys. Rev. Lett. 62，1524（1989）]。用这个拟合参数，我们能够计算系统的弹性模量，并找到与现有数据的良好协议。
Phase Diagram and Criticality of the Modified Primitive Electrolyte Model in Bulk and in Inert and Conducting Confinement
Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart（斯图加特大学）；Institute for Computational Physics, University of Stuttgart（斯图加特大学计算物理研究所）；Institute for Physics of Functional Materials, Hamburg University of Technology（汉堡工业大学功能材料物理研究所）
Phase Separation in Charge-Stabilized Colloidal Suspensions: Influence of Nonlinear Screening
电荷稳定的胶体悬浮液的相行为是由静电粒子间相互作用的响应理论和自由能的变分理论相结合。整合出自由度的微离子（抗衡离子，盐离子），宏离子-微离子混合物被映射到一个单组分系统有效的宏离子相互作用。微离子对大离子静电势的线性响应导致屏蔽库仑（Yukawa）有效对势和单体体积能量，而非线性响应修改有效相互作用[A. R. Denton，\PR E { \bf 70}，031404（2004）]。基于热力学微扰理论，将体积能和有效对势作为变分自由能的输入。对于线性和一阶非线性有效相互作用，应用于高电荷大离子和单价微离子的水悬浮液的共存分析在临界盐浓度以下产生大离子富集相和大离子贫乏相的本体分离，与相关线性化理论的预测定性一致[R. van Roij，M. Dijkstra和J. - P. Hansen，\PR E { \bf 59}，2010（1999）; P. B. Warren，\JCP { \bf 112}，4683（2000）].它的结论是，非线性屏蔽可以修改相行为，但不一定抑制去离子悬浮体的体相分离。
