# Difference between revisions of "Zeno line"

The Zeno line is the name given to a line along which the compressibility factor is unity [1]

$Z:= \frac{pV}{Nk_BT}=1$

## Batchinsky law

The Batchinsky law [2], derived from the van der Waals equation of state, states that:

$\frac{\rho}{\rho_B} + \frac{T}{T_B} = 1$

where $\rho_B$ is the value of the density obtained by the extrapolating the coexistence curve into the low temperature region beyond the triple point, and $T_B$ is the Boyle temperature, which is $a/bR$.

## References

1. D. Ben-Amotz and D. R. Herschbach, "Correlation of the Zeno (Z=1) line for supercritical fluids with vapor-liquid rectilinear diameters", Israel Journal of Chemistry 30 pp. 59-68 (1990)
2. A. Batschinski "Abhandlungen über Zustandsgleichung; Abh. I: Der orthometrische Zustand", Annalen der Physik 19 pp. 307-309 (1906)