SHIFT-INDEPENDENT NUCLEAR-SPIN DIFFUSION BY SLOW MAGIC-ANGLE SAMPLE-SPINNING FOR THE EXPLORATION OF SOLIDS

An improved spin-diffusion experiment for the exploration of local ord er in solids is described. By slow magic-angle sample spinning, it is possible to remove the dependence of the spin diffusion rate on the ch emical shift difference between two interacting nuclear spins, while t he informative chemical shielding anisotropy is fully retained. Slow m agic-angle spinning shortens the time necessary for the spin system to reach the quasi-equilibrium state, and it allows for rapid spin diffu sion also in the absence of heteronuclear dipolar interactions in cont rast to static or rapidly spinning samples. The feasibility of the exp eriment is demonstrated for a sample of carbon-13 labelled amorphous a tactic polystyrene.