Rotational Spin–Lattice and Spin–Spin Quadrupole Relaxation in Perdeuterated Glycerol

Abstract

The deuteron spin–lattice and spin–spin relaxation times have been measured in glycerol‐d₈ at the resonance frequency of 5 MHz and over the temperature range from − 25 to + 70°C using “spin–echo” techniques. The spin–lattice relaxation times exhibit a minimum at − 13°C and this minimum value is employed in directly determining the value of the deuteron quadrupole coupling constant (DQCC) in glycerol. Values of the DQCC obtained lie between 139 and 158 kHz. These values of the DQCC and the measured relaxation times were employed to determine the average correlation times ${\mathrm{(\tau ̄}}_Q)$ for the molecular motions responsible for the quadrupolar relaxation. These correlation times are associated with the rotational reorientation of the molecules. A comparison of ${\mathrm{\tau ̄}}_Q$ with the average dielectric relaxation times indicates that the rotational reorientation of glycerol is best described as large‐angle jump diffusion.