Tetrahedral hard sphere model

The tetrahedral hard sphere model consists of four hard spheres located on the vertices of a regular tetrahedron.

Second virial coefficient

The second virial coefficient is given by ( Eq.5):

${\frac {B_{2}^{*}}{4V_{m}^{*}}}=1+{\frac {UL^{*}+VL^{*3}}{4}}$

where $L^{*}$ is the reduced elongation, $V_{m}^{*}$ is the corresponding reduced volume, $U=0.72477$ and $V=4.730$.

Equation of state

The equation of state is given by ( Eq. 17):

${\frac {\beta P}{\rho }}={\frac {1+(1+UL^{*}+VL^{*3})y+(1+WL^{*}+XL^{*4})y^{2}-(1+ZL^{*3})y^{3}}{(1-y)^{3}}}$

where $U=0.72477$, $V=4.730$, $W=1.3926$, $X=24.78$ and $Z=7.69$.