Multiple-quantum magic-angle spinning MQ-MAS

Yet another solution to the problem, known as multiple-quantum magic-angle spinning (MQ-MAS) relies on the fact that B2 and B4 are functions of 7, p, Yj, a and 8, where p is the order of the multiquantum coherence and a and P are the Euler angles corresponding to the orientation of each crystallite in the powder with respect to the rotor axis. Under fast MAS, the chemical shift anisotropy, heter-onuclear dipolar interactions and the term proportional to P2 in Equation [20] are removed, so that... [Pg.381]

Multiple-Quantum Magic-Angle Spinning Spectroscopy ( Al MQ/MAS NMR)... [Pg.79]

Abstract Recent advances in nuclear magnetic resonance spectroscopy of quadrupolar (/> 1/2) nuclei with half-integer spins in solids have been reviewed. The advent of multiple-quantum (MQ) magic-angle spinning (MAS) spectroscopy gave new momentum to the study of quadrupolar nuclei in materials of academic and industrial interest such as min-... [Pg.141]

In the first part (Section 5.2), various solid state NMR techniques, such as magic angle spinning (MAS), cross polarization (CP), multiple-quantum (MQ) and multidimensional spectroscopies, pertinent to obtain high resolution NMR spectra in Al-based fluorides, are presented. They allow the precise determination of the isotropic chemical shift and Al iso and quadrupolar parameters or reveal or - Al proximities. [Pg.142]

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