Rotational Relaxation in Polar Gases. III. Molecular Dynamics

A 50 molecule sample in contact with a heat bath of similar molecules was used as a model to calculate the rotational collision numbers, $Z_{\mathrm{rot}}$ , for HCl and DCl at 300 and 500°K, by the method of molecular dynamics. The mean rotational energy of the sample exhibits an exponential approach to a steady state value; however, there was considerable scatter about the exponential curve. The results for $Z_{\mathrm{rot}}$ generally agree with previous theoretical calculations. They are intermediate to experimental acoustic data and the earlier perturbation results.