Ionic fluid criticality lattice models

Concerning the fluid some possibilities for tricriticality are discussed. The GDH theory predicts an order-transition between the isotropic fluid and a phase with periodic charge density waves [94], The corresponding transition line cuts the liquid-liquid line near their critical point, so that a tricritical point is a possibility. The possible presence of both, gas-liquid and tricritical points in ionic fluids has been predicted by Ciach and Stell [96] for a model, in which additional short-range forces supplement the lattice Coulomb forces. 

The two-term crossover Landau model has been successfully applied to the description of the near-critical thermodynamic properties of various systems, that are physically very different the 3-dimensional lattice gas (Ising model) [25], one-component fluids near the vapor-liquid critical point [3, 20], binary liquid mixtures near the consolute point [20, 26], aqueous and nonaqueous ionic solutions [20, 27, 28], and polymer solutions [24]. 

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