The gas-liquid coexistence region of a primitive model electrolyte in the mean electrostatic potential approach

Abstract

Using the modified Poisson-Boltzmann (MPB) and symmetric Poisson-Boltzmann (SPB) theories we have obtained the coexistence curve and related transition properties of a primitive model (PM) electrolyte. For the restricted PM case fairly good agreement is found between the MPB and recent Monte Carlo results. A broadening of the coexistence region and a displacement of the critical point are the suggested consequences of considering size asymmetric electrolytes. In the vicinity of the critical point examined here the MPB and SPB theories display a mean-field value for the associated critical exponent β.