The application of the two frequency composite pulses for NQR detection of nitrogen-based compounds

Multifrequency ¹⁴ N nuclear quadrupole resonance (NQR) signals induced due to irradiation by twofrequency composite pulses have been studied. The experiments have been performed on RDX explosive at room temperature. It has been shown that the NQR signal at the observed transition can be essentially enhanced by use of the two-frequency composite pulses. Moreover, it is possible to excite and maintain the precession signal at the third, nonirradiated frequency. We have also shown that the twofrequency composite pulse can be applied as the preparatory pulse for increasing the NQR signal in multipulse sequences.