The theory relevant to the observation of nuclear magnetic resonance of dilute impurities in solids, by the change in the gamma- and beta-ray emission distributions from oriented nuclei, is discussed for the situation where an electric quadrupole interaction produces a splitting of the nuclear magnetic resonance line comparable with the interaction energy with the applied RF field. The major deviations from conventional adiabatic fast passage expected for a single sweep of the RF frequency through the resonance condition are shown to be well reproduced by recent experimental results, indicating the validity of the theoretical model discussed.