TOWARDS THE DETECTION OF EXPLOSIVE TAGGANTS: MICROWAVE AND MILLIMETER-WAVE GAS PHASE SPECTROSCOPIES OF 3-NITROTOLUENE

The monitoring of gas phase mononitrotoluenes is crucial for defence, civil security and environmental interests since they are used as taggant for TNT detection and in the manufacturing of industrial compounds such as dyestuffs. We have succeeded to measure and analyse at high resolution the room temperature rotationally resolved millimeter-wave spectrum of 3-nitrotoluene (3-NT). Experimental and theoretical difficulties have been overcome, in particular, those related to the low vapour pressure of 3-NT and to the internal rotation of a $\mathrm{CH_3}$ in almost free rotation regime ($V_3$=6.7659(24)~cm$^{-1}$). Rotational spectra have been recorded in the microwave and millimeter-wave ranges using a supersonic jet Fourier Transform microwave spectrometer (${T_{rot}}