Distribution of free flight times in a hard sphere gas

Using a simple functional relation the distribution of the times of free flight in a classical gas of hard spheres is shown to depend only on two specific combinations of the molecular and thermodynamic parameter. This distribution has been calculated with molecular dynamics for three values of the density. The behaviour of the function is found to be qualitatively similar to its form in the low density limit, even for densities for which the system is far into the crystalline phase.