Monte Carlo simulations of the critical properties of the restricted primitive model

Abstract

Recent Monte Carlo simulations of the critical point of the restricted primitive model for ionic solutions are reported. Only the continuum version of the model is considered. A finite size scaling analysis based in the BruceWilding procedure gives critical exponents in agreement with those of the three-dimensional Ising universality class. An anomaly in the scaling of the specific heat with system size is pointed out.

Monte Carlo simulation of the nonadditive restricted primitive model of ionic fluids: Phase diagram and clustering

“…We stress that our data do not extend sufficiently close to the critical region to allow quantitative estimates of critical exponents and non universal quantities, still we used the above functional forms as convenient fitting formulae, able to capture the typical flatness of the fluid coexistence curves [52]. The pure RPM is believed [28,[55][56][57] to belong to the three-dimensional Ising universality class so we choose β I = 0.325, α I = 0.11, and ∆ I = 0.51. We are then able to fit the pure RPM case, ∆ = 0, for which we find the critical point at ρ * c = 0.0319 and T * c = 0.0476, the RPM with positive nonadditivity, ∆ = +0.1, for which the critical point is found at ρ * c = 0.0275, T * c = 0.0432, and the RPM with negative nonadditivity, ∆ = −0.1, for which ρ * c = 0.0495, T * c = 0.0526.…”