A NUCLEAR MAGNETIC RESONANCE STUDY OF ANISOTROPIC MOLECULAR ROTATION IN LIQUID CHLOROFORM AND IN CHLOROFORM-BENZENE SOLUTION

The nuclear spin relaxation times of the deuteron and chlorine-35 in the symmetric-top molecules CDCl3 and CHCl3 and in two equimolar mixtures CDCI3-C6H6 and CHCI3-C6D6 have been measured as a function of temperature. The reorientation of the molecules in these liquids is shown to be anisotropic. A rotational diffusion equation is assumed for the motion, and the rotational diffusion constants D∥ and D⊥ are calculated from the relaxation times of chloroform in the neat liquid and for the chloroform and benzene in the mixtures. The change in the reorientation of chloroform molecules between neat and benzene solution is interpreted in terms of the formation of a complex between chloroform and benzene.