Gas-liquid critical point in model ionic fluids with charge and size asymmetry

Abstract

We study the effects of size and charge asymmetry on the gas‐liquid critical parameters of a primitive model (PM) of ionic fluids. The model is characterized by the two parameters: hard‐sphere diameter‐, λ = σ+/σ− and charge, z = q+/|q−|, ratios of the two ionic species. Using the collective variables based theory we calculate the critical temperature and the critical density for the two versions of PM: an equisize PM with charge asymmetry (λ = 1, z≠1 and a monovalent PM with size asymmetry (λ≠1, z = 1). The trends obtained for the both critical parameters of the models under consideration agree qualitatively with Monte Carlo simulation findings.