Liquid-gas separation in colloidal electrolytes

Abstract

The liquid-gas transition of an electroneutral mixture of oppositely charged colloids, studied by Monte Carlo simulations, is found in the low temperature -- low density region. The critical temperature shows a non-monotonous behavior as a function of the interaction range, $\kappa^{-1}$, with a maximum at $\kappa \sigma \approx 10$, implying an island of coexistence in the $\kappa$-$\rho$ plane. The system is arranged in such a way that each particle is surrounded by shells of particles with alternating charge. In contrast with the electrolyte primitive model, both neutral and charged clusters are obtained in the vapor phase