Virial coefficients and demixing of athermal nonadditive mixtures

Abstract

We compute the fourth virial coefficient of a binary nonadditive hard-sphere mixture over a wide range of deviations from diameter additivity and size ratios. Hinging on this knowledge, we build up a $y$ expansion [B. Barboy and W. N. Gelbart, J. Chem. Phys. {\bf 71}, 3053 (1979)] in order to trace the fluid-fluid coexistence lines which we then compare with the available Gibbs-ensemble Monte Carlo data and with the estimates obtained through two refined integral-equation theories of the fluid state. We find that in a regime of moderately negative nonadditivity and largely asymmetric diameters, relevant to the modelling of sterically and electrostatically stabilized colloidal mixtures, the fluid-fluid critical point is unstable with respect to crystallization.

28 pages, 9 figures, to appear in J. Phys. Chem. B

References in corpus (2)

• Equation of state of non-additive $d$-dimensional hard-sphere mixtures
• Thermodynamic stability of fluid-fluid phase separation in binary athermal mixtures: The role of nonadditivity

Cited by in corpus (5)

• Binary non-additive hard sphere mixtures: Fluid demixing, asymptotic decay of correlations and free fluid interfaces
• Virial coefficients, thermodynamic properties, and fluid-fluid transition of nonadditive hard-sphere mixtures
• Population inversion of a NAHS mixture adsorbed into a cylindrical pore
• Fourth virial coefficient of additive hard-sphere mixtures in the Percus-Yevick and hypernetted-chain approximations
• Fourth virial coefficients of asymmetric nonadditive hard-disc mixtures