Tejero and Cuesta hard disk equation of state

The Tejero and Cuesta hard disk equation of state is given by (Ref. 1 Eq. 3.10)

$Z (\eta)= \frac{1+\sum_{n=1}^6 C_n \eta^n}{(1-\eta)^2}$

where

$C_1$	0
$C_2$	0.128018
$C_3$	0.0018188
$C_4$	-0.72553
$C_5$	2.52783
$C_6$	-2.4945

$\eta$ is the packing fraction and Z is the compressibility factor.

References

1. C. F. Tejero and J. A. Cuesta "Hard-sphere and hard-disk freezing from the differential formulation of the generalized effective liquid approximation", Physical Review E 47 pp. 490-495 (1993)