Ballone-Pastore-Galli-Gazzillo

The Ballone-Pastore-Galli-Gazillo (BPGG) (1986) (Eq. 3.8 Ref. 1) closure relation, developed for hard sphere mixtures, is given by

$B(r)=\left[1+s\gamma \left(r\right)\right]^{1/s}-1-\gamma \left(r\right)$

where $s=15/8$. It has its origins in the Martynov-Sarkisov closure ($s=2$). The value of $s$ can be determined by a self-consistency condition. Notice that for $s=1$ the BPGG approximation reduces to the hyper-netted chain closure.

References

1. P. Ballone; G. Pastore; G. Galli; D. Gazzillo "Additive and non-additive hard sphere mixtures" Molecular Physics, 59 pp. 275-290 (1986)