Self-Diffusion Coefficients in Plastic Crystals by Multiple-Pulse NMR in Large Static Field Gradients

Measurements of self-diffusion coefficients in solids with the gradient spin echo technique have until now been limited due to short spin-spin relaxation times. Here we make use of multiple-pulse sequences, which average out the nuclear dipole interaction, to expand the measurable range for macroscopic self-diffusion coefficients by 2 orders of magnitude. By combining multiple-pulse NMR, in our case using the MREV-8 sequence, with a high static gradient we measured the self-diffusion coefficient in a molecular crystal of camphene down to a value of D0ex0ex=0ex0ex3×10^-16m²s^-1 at 219 K in the plastic phase.