J. Phys. IV France
Volume 10, Numéro PR5, March 2000
The 1999 International Conference on Strongly Coupled Coulomb Systems
Page(s) Pr5-17 - Pr5-17
The 1999 International Conference on Strongly Coupled Coulomb Systems

J. Phys. IV France 10 (2000) Pr5-17-Pr5-17

DOI: 10.1051/jp4:2000502

Correlation lengths in electrolytes : Exact results and sensible approximations

M.E. Fisher

Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742-2431, U.S.A.

Reliably understanding the phase behavior of basic models for ionic systems is still an important task for theory and one that has experimental relevance, particularly for the critical neighborhood of liquid electrolytes [1, 2]. To that end, exact calculations [3-5] of the charge and density correlations lengths (including the Lebowitz length) for hard-sphere electrolytes of general valences, Zσ, and diameters, aστ , have been undertaken using Meeron's diagrammatic analysis [J. Chem. Phys. 28 (1958) 630-643] and the hyper-netted chain graphical resummation. A variety of "universal" types of divergent behavior and leading nonuniversal corrections are found when the overall ionic density approaches zero. The approximate "generalized Debye-Hückel" theories [6-8], which yield charge and density correlation functions for the restricted primitive model (σ τ ± aστ), may be tested and prove exact as regards the universal behavior at low densities. The critical region, however, still poses profound problems (see, e.g., [9]).1

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