Determination of Nuclear Quadrupole Coupling Constants from Nuclear Magnetic Resonances in Polycrystalline Solids

The line shape of a nuclear magnetic resonance in a polycrystalline solid under the influence of an axially symmetric second-order nuclear quadrupole perturbation has been calculated for 20 values of the quadrupole coupling constant. From these calculations the frequency difference between the peaks in the derivative of the resonance line has been found as a function of the quadrupole coupling constant. This relationship has been shown to be useful in two cases. First, a procedure is described for determining the quadrupole coupling constant by studying the resonance as a function of magnetic field, when it is known that the electric-field-gradient asymmetry parameter is zero. Second, when both first- and second-order quadrupole effects can be observed in a polycrystalline solid, a method is described for determining both the quadrupole coupling constant and the electric field gradient asymmetry parameter for small values of the asymmetry parameter.