Research on Interionic Forces in Solution

While the McMillan-Mayer theory (Section 4) prescribes the iiabir) as functionals of the Hamiltonian of a BO-level model, little has been learned from this sort of direct approach. The main contributions are an analytical study of charged hard spheres in an uncharged hard-sphere solvent by Stell, Monte Carlo and molecular dynamics studies of somewhat more realistic models, and a study using the mean spherical approximation (Section 7.3).  

Although these studies may provide the basis for important future developments, in most of them the solvent-averaged potentials Uab for anion-cation pairs have such deep minima that in a physical model the ions would be largely associated into ion pairs or larger clusters at concentrations above 10 M. One should therefore be cautious when comparing the results of these studies directly to those real ionic systems in which the solute is largely ionized, even above 1M electrolyte concentration. 

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