Correlation of deuterium quadrupolar tensor orientation via spin diffusion under slow magic-angle sample spinning

A two-dimensional 2H spin-diffusion experiment for the characterization of solids is described. The experiment utilizes slow magic-angle sample spinning to enhance 2H spin diffusion while the informative 2H quadrupolar spin interactions are fully retained as in static samples. Energy-level crossing induced by slow sample rotation at the magic angle enhances 2H spin diffusion, and the polarization transfer becomes nearly frequency-independent even for large quadrupolar splittings. The utility of the two-dimensional 2H spin-diffusion experiment with slow magic-angle spinning is demonstrated by applications to deuterated crystalline samples. Accurate intra- and inter-molecular angular information on the orientation of quadrupolar tensors is obtained from the measurements.