Structures and properties of hard sphere mixtures based on a self-consistent integral equation

A new self-consistent closure is formulated for the additive hard sphere mixtures at high densities (η=0.49) within the Ornstein–Zernike integral equation approach. Diameter ratios (σSS/σBB) from 0.3 to 0.9 and several compositions are examined. The consistencies include the thermodynamic ones (e.g., pressure consistency, and Gibbs–Duhem relation), and the structural ones (e.g., the zero-separation theorems). The bridge functions have built-in “flexibility” that can be adapted to the consistency requirements. Comparison with Monte Carlo simulation shows that the present closure yields highly accurate results. The contact values and zero-separation values are more accurate than those obtained from the conventional closures, such as the Percus–Yevick and Martynov–Sarkisov closures. A structural theory for hard sphere mixtures has been formulated that is accurate and consistent at the same time.