A magic-angle turning NMR experiment for separating spinning sidebands of half-integer quadrupolar nuclei

A two-dimensional magic-angle turning NMR experiment is described for separating spinning sidebands of half-integer quadrupolar nuclei. The experiment is an alternative to quadrupolar phase-adjusted sideband separation (QPASS) [Chem. Phys. Lett. 272 (1997) 295] that yields infinite speed spectra in one dimension and spinning sideband manifolds in the other dimension. A shear transformation is introduced for processing of quadrupolar magic-angle turning (QMAT) data with time evolution of only one rotor period. The QMAT experiment has the advantages of averaging the first-order modulation of the pulse sequence efficiencies giving smaller residual spinning sidebands, linearly incrementing pulse timings for convenient practical implementation, and easily adjustable pulse spacings suitable for higher spinning frequencies.