FREEZING OF SIMPLE FLUIDS IN TERMS OF THE ORNSTEIN-ZERNIKE EQUATION - SOFT-SPHERE FLUIDS AND BINARY HARD-SPHERE MIXTURES

The solution of the Martynov-Sarkisov closure (MS) of the Ornstein-Zernike equation has to satisfy the condition for the mean force potential w greater-than-or-equal-to - 1. It is shown both for one-component soft-sphere fluids and for two-component hard-sphere mixtures that densities at which this condition becomes broken are close to the freezing densities provided by computer simulation (CS). For pressure data, the agreement between MS and CS is rather poor. In particular, for hard-sphere mixtures, MS exhibits only the spindle-type diagram while CS presents also azeotropic and eutectic forms.