Cl35 Pure Quadrupole Resonance Studies of Relaxation Times in Solid Solutions of p-Dichlorobenzene

Transient methods have been used to measure the Cl35 nuclear relaxation times at room temperature in solid solutions of p-dichlorobenzene and p-dibromobenzene. The spin-lattice relaxation time T1 and the phase memory time T2 were found to be virtually independent of sample composition. However, the inverse line width T2* decreases very sharply from 3.1×10—4 sec in pure p-dichlorobenzene to 0.15×10—4 sec in a sample with 20 mole percent p-dibromobenzene. Thus, the main effect of the solute molecules is to broaden the absorption line by producing a distribution in the electric field gradients at the chlorine nuclei. Mechanisms for the T1 and T2 results are discussed.