Multiple quantum magic

In the vast majority of cases where NMR is used to localise cations in zeolites, one or both of the following techniques is used Magic Angle Spinning (MAS) or Multiple Quantum Magic Angle Spinning (MQMAS). 

Medek, A., Harwood, ).S., and Frydman, L (1995) Multiple-quantum magic- angle spinning NMR a new method for the study of quadrupolar nuclei in solids. /. Am. Chem. Soc., 117, 12779-12787. 

Goldbourt, A. and Madhu, P.K. (2005) Multiple-quantum magic-angle spinning high-resolution NMR spectroscopy of half-integer spin quadrupolar nuclei. Annu. Rep. NMR Spectrosc., 54, 81-153. 

MQMAS NMR multiple quantum magic-angle spinning NMR... 

R. Lefort, J. W. Wiench, M. Pruski and J.-P. Amoureux, Optimization of data acquisition and processing in Carr-Purcell-Meiboom-Gill multiple quantum magic angle spinning nuclear magnetic resonance. /. Chem. Phys., 2002,116, 2493-2501. 

In order to remove the anisotropic effects of quadrupolar interactions which can obscure MAS spectra other techniques such as Double Rotation (DOR) [18, 19], Dynamic Angle Spinning (DAS) [18] or Multiple Quantum Magic Angle Spinning (MQMAS) have to be employed. Of these the most simple to apply practically is MQMAS, which can be conducted on a standard MAS-equipped NMR spectrometer. A number of texts and review papers discuss MQMAS in significant technical detail [20, 21]. 

Progress in Multiple-Quantum Magic-Angle Spinning NMR Spectroscopy... 

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