Generalized cubic equation of state and the radial distribution functions at contact for multi-component hard-sphere mixtures with large size ratio

- A two parameter generalized cubic (GC) EOS for hard sphere fluids is proposed.
- The EOS is extended to mixtures merely demanding of the EOS also is cubic.
- The two parameters are determined by fitting virial coefficients of pure fluid.
- The results of virial coefficients and compressibility factors are excellent.
- The values of RDFC for mixtures are far better than expressions in literature.

A generalized cubic (GC) equation of state (EOS) with two independent parameters is proposed. The GC EOS can include EOS from both virial and compressibility routes of Percus-Yevick theory in it as special cases. The two parameters are determined by fitting well-known virial coefficients of pure fluid. The generalized cubic EOS can be directly and consistently extended to multi-component mixtures merely demanding of the EOS of mixtures also is cubic, and combining two strict physical conditions for the radial distribution functions at contact (RDFC) of mixtures. The calculated virial coefficients of pure fluid and predicted compressibility factors and RDFC for both pure fluid and mixtures are excellent as compared with the simulation data. The values of RDFC for mixtures with extremely large size ratio are far better than the expressions in literature.