H-N-14 double resonance of TNT from a land mine

The N-14 NQR spectrum of one gram of military grade trinitrotoluene (TNT) o btained from an abandoned land mine has been determined by H-1-N-14 nuclear quadrupole double resonance at room temperature. The magnetic field depend ence of the proton spin-lattice relaxation time Tr as well as the N-14 T-1 of TNT were determined as well. The use of a double frequency irradiation t echnique allowed for a unique assignment of the twelve observed lines to th e v(+) and v(-) N-14 transitions of the six chemically non-equivalent cryst allographic nitrogen sites in the unit cell. Nuclear quadrupole double reso nance results in an increase in the N-14 signal to noise ratio by a factor of 30 as compared to conventional NQR and a significant reduction of the me asuring time which is important in the detection of explosives.