The pressure dependence of molecular motion in solid benzene studied by N.M.R.

Abstract
The proton N.M.R. relaxation times, T 1 and T , of solid benzene have been measured as a function of hydrostatic pressure up to 1·8×108 Pa. The T 1 measurements are analysed in terms of the reorientational motion of the molecules. This molecular motion is found to have a weak pressure dependence and an associated activation volume of 0·18 of the molar volume, VM . The T measurements are analysed in terms of the translational self-diffusion of the molecules. This motion has a strong pressure dependence and an activation volume ΔV *, of 1·4±0·2 of the molar volume was obtained, which is consistent with a vacancy diffusion mechanism.