Hard sphere model
The hard sphere interaction potential is given by
V(r) = ∞,  if r <  σ; and 
V(r) = 0; if r ≥ σ.
where V(r) is the potential energy between two spheres at a distance r, and σ is the sphere diameter.
The hard sphere interaction potential is given by
V(r) = ∞,  if r <  σ; and 
V(r) = 0; if r ≥ σ.
where V(r) is the potential energy between two spheres at a distance r, and σ is the sphere diameter.