Ionic criticality : an exactly soluble model

Jean-Noël Aqua (1, 2) , Michael E. Fisher (2)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre
2 IPST - Institute for Physical Science and Technology [College Park]

Gas-liquid criticality in ionic fluids is studied in exactly soluble spherical models that use interlaced sublattices to represent hard-core multicomponent systems. Short-range attractions in the uncharged fluid drive criticality, but charged ions do not alter the universality class. Debye screening remains exponential at criticality in fully ion-symmetric 1:1 models. However, ionic asymmetry couples charge and density fluctuations in a direct manner: The charge correlation length then diverges precisely as the density correlation length and the Stillinger-Lovett rule is violated at criticality.

Mots clés: Electrolytes; fluids; fluctuations; points

Domaines: Mécanique statistique [cond-mat.stat-mech]

Jean-Noël Aqua, Michael E. Fisher. Ionic criticality : an exactly soluble model. Physical Review Letters, 2004, 92, pp.Art. 135702. ⟨10.1103/PhysRevLett.92.135702⟩. ⟨hal-00083897⟩