NMR-SPECTRA FROM POWDERED SOLIDS SPINNING AT ANY ANGLE AND SPEED - SIMULATIONS AND EXPERIMENTS

A new method is described for calculating NMR spectra of powdered solids spinning at any speed and at any angle relative to the magnetic field. The algorithm provides the intensities and shapes of the centreband and all sidebands through a computation involving the solution of homogeneous linear equations. The method is also applicable to cases where two or more interactions simultaneously affect the spectral response. A simple extension of the algorithm treats cases where an analytical expression for the resonance frequency is not available. The method is demonstrated with simulations and experimental examples of anisotropic chemicai-shift spectra obtained by spinning samples at various low speeds and angles. The technique is also applied to a spin-1 nucleus with both an anisotropic chemical shift and a dipolar coupling either to a heteronuclear spin-5 nucleus or to a spin-1 nucleus experiencing a strong quadrupole interaction. © 1990 Taylor and Francis Ltd.