Crystallization of Colloidal Plasma: Model of Charge Renormalization with Addition of Salt

A new procedure is suggested for macroion charge renormalization, which describes the melting curve of charged colloidal liquids as a function of concentration of added salt. The method is based on the gel model approximation with new boundary conditions for the minor-ion charge density (counterions and ions of salt). The renormalized macroion charge is determined using the requirement of coincidence of the minor-ion charge density in nonlinear and linear approximations over the mean distance between macroions. The obtained correlation between the true and renormalized charges differs from the previously known correlations for both the Poisson-Boltzmann cell model and the Poisson-Boltzmann gel model. Good agreement is found with the experimentally obtained melting curve without any additional corrections or fitting parameters, in particular, those associated with the inclusion of surface chemical processes.