title: Monte Carlo simulation of the nonadditive restricted primitive model of ionic fluids: phase diagram and clustering.
abstract: We report an accurate Monte Carlo calculation of the phase diagram and clustering properties of the restricted primitive model with nonadditive hard-sphere diameters. At high density the positively nonadditive fluid shows more clustering than in the additive model and the negatively nonadditive fluid shows less clustering than in the additive model; at low density the reverse scenario appears. A negative nonadditivity tends to favor the formation of neutrally charged clusters starting from the dipole. A positive nonadditivity favors the pairing of like ions at high density. The critical point of the gas-liquid phase transition moves at higher temperatures and higher densities for a negative nonadditivity and at lower temperatures and lower densities for a positive nonadditivity. The law of corresponding states does not seem to hold strictly. Our results can be used to interpret recent experimental works on room temperature ionic liquids.
authors.affiliation: Dipartimento di Scienze dei Materiali e Nanosistemi, Università Ca' Foscari Venezia, Calle Larga S. Marta DD2137, I-30123 Venezia, Italy. rfantoni@ts.infn.it
authors.forename: Riccardo
authors.initials: R
authors.lastname: Fantoni
authors.forename: Giorgio
authors.initials: G
authors.lastname: Pastore
mesh_terms: D003198:Computer Simulation; D052578:Ionic Liquids / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D009010:Monte Carlo Method; D044367:Phase Transition
chemical_list: D052578:Ionic Liquids