Selective and non-selective NMR excitation of quadrupolar nuclei in the solid state

Abstract

Spectral intensities of quadrupolar nuclei and the radiofrequency (rf) pulse lengths for selective and non-selective excitation of any single-quantum NMR transition in the solid state are calculated. When nuclei of the same element occupy sites which experience different electric field gradients, the spectra are quantitatively reliable only when the length of the rf pulse is much smaller than π/2ω rf√ I( I+1)− m( m+1). By using hydrated samples and short rf pulses, quantitative determination of aluminium by 27Al NMR in thermally treated (ultrastable) zeolite Y has been achieved. Quadrupole nutation NMR reveals novel information about the various aluminium species present.