An analysis of sideband suppression techniques in magic-angle sample spinning NMR

Several theoretical and experimental aspects of sideband suppression in the NMR spectra of rotating solids are considered. We show that consideration of the alignment of individual spin packets in the rotating frame leads directly to an explanation of the mechanism of sideband suppression in the total suppression of sidebands (TOSS) experiment. In addition, variants of the TOSS experiment that use six instead of four π pulses are introduced. The extra π pulses allow greater flexibility in the interpulse spacings and two new sequences are presented. It is also shown that dipolar suppression and sideband suppression techniques may be combined to yield spectra containing only centerband resonances of unprotonated nuclei.