Spinning sideband summation for quadrupole MAS NMR spectra using a magic-angle turning technique

Two-dimensional (2D) magic-angle spinning (MAS) NMR measurements for unravelling the overlapping spinning sidebands (SSBs) for quadrupolar nuclei having half-integer spins were reported; the method utilizes a magic-angle turning technique recently exploited for chemical-shift spectra. The projection of the resultant 2D spectrum reconstructs the inherent MAS lineshapes without SSBs, which can be straightforwardly analyzed to yield quadrupolar parameters. The SSB-free Na-23 MAS spectrum for Na2SO4, which would otherwise be observed under an infinite spinning speed, was obtained.