Hard sphere model

Interaction Potential

The hard sphere interaction potential is given by

V (r) = {\begin{matrix} \infty & ; & r < σ \\ 0 & ; & r \geq σ \end{matrix}

where $V (r)$ is the potential energy between two spheres at a distance $r$ , and $σ$ is the sphere diameter.

Hard sphere fluid:

Hard disks in a 2-dimensional space

Hard rods in one dimension

Virial coefficients of hard spheres and hard disks