The restricted primitive model of ionic fluids with nonadditive diameters
1 Dipartimento di Scienze dei Materiali e Nanosistemi, Università Ca' Foscari Venezia Calle Larga S. Marta DD2137, I-30123 Venezia, Italy, EU
2 Dipartimento di Fisica dell' Università and IOM-CNR - Strada Costiera 11, I-34151 Trieste, Italy, EU
Received: 7 November 2012
Accepted: 8 February 2013
The restricted primitive model with nonadditive hard-sphere diameters is shown to have interesting and peculiar clustering properties. We report accurate calculations of the cluster concentrations. Implementing efficient and ad hoc Monte Carlo algorithms we determine the effect of nonadditivity on both the clustering and the gas-liquid binodal. For negative nonadditivity, tending to the extreme case of completely overlapping unlike ions, the prevailing clusters are made of an even number of particles having zero total charge. For positive nonadditivity, the frustrated tendency to segregation of like particles and the reduced space available to the ions favors percolating clusters at high densities.
PACS: 68.43.Hn – Structure of assemblies of adsorbates (two- and three-dimensional clustering) / 61.20.Qg – Structure of associated liquids: electrolytes, molten salts, etc. / 64.70.pv – Colloids
© EPLA, 2013