A simple procedure for the determination of the quadrupole interaction parameters and isotropic chemical shifts from magic angle spinning NMR spectra of half‐integer spin nuclei in solids

Abstract

A simple procedure is presented for the determination of the asymmetry parameter of the electric field gradient, the quadrupole coupling constant, the second‐order quadrupolar shift and the isotropic chemical shift of quadrupolar nuclei with half‐integer spin directly from the experimental magic angle spinning (MAS) NMR spectra of powder samples measured at a single magnetic field. General equations applicable to any half‐integer spin nucleus and the specific expressions for ²³Na and ²⁷ Al are given. The simple calculations can easily be performed with a pocket calculator and avoid any spectral simulation or lengthy computer work. The method was applied to a series of ²³Na MAS NMR spectra of selected sodium compounds and the agreement of the results with those of computer simulations is demonstrated.