Pulsed double resonance in the pure quadrupole regime: off-resonant DRRF technique for detection of rare quadrupolar nuclei

A scheme for the detection of rare quadrupolar nuclei based on off-resonant pulse excitation of the abundant quadrupolar nuclei coupled to the rare ones in the sample has been outlined and demonstrated. Pure quadrupole resonance spectrum of ²³Na in poly-crystalline samples of sodium chlorate has been thus recorded at room temperature. The present double resonance scheme in the pure quadrupole regime is marked by a substantial reduction in spectrometer transmitter power and hardware requirements.