The Vega equation of state for an isotropic fluid of hard (biaxial) ellipsoids is given by (Ref. 1 Eq. 20):
where is the compressibility factor and is the volume fraction, given by
where is the number density.
The virial coefficients are given by the fits
and
where
- ,
and
where is
the volume, , the surface area, and the mean radius of curvature.
For see B_2 for any hard convex body.
References
- Carlos Vega "Virial coefficients and equation of state of hard ellipsoids", Molecular Physics 92 pp. 651-665 (1997)
- Carl McBride and Enrique Lomba "Hard biaxial ellipsoids revisited: Numerical results", Fluid Phase Equilibria (2007)