Rotor synchronization of radiofrequency and gradient pulses in high-resolution magic angle spinning NMR

We have investigated the extent to which rotor synchronization of radiofreq uency pulses leads to spectral improvement in high-resolution magic angle s pinning NMR experiments. Several pulse sequences were tested, and the effec t was found to be maximal in homonuclear TOCSY spectra. The physicochemical nature of the sample plays a role in the phenomenon, as rotor synchronizat ion allows the refocusing of residual anisotropic interactions. However, ev en in a liquid sample the effects were visible. Radial inhomogeneities of t he radiofrequency field were identified as an important source of the probl em. (C) 2001 Academic Press.