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 ([1] Eq.5):
where is the reduced elongation, is the corresponding reduced volume, and .
Equation of state
The equation of state is given by ([1] Eq. 17):
where , , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle W=1.3926}
, Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle X=24.78}
and Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Z=7.69}
.