Terahertz absorption measurement for gas-phase 2,4-dinitrotoluene from 0.05 THz to 2.7 THz

We report the first known vapor-phase spectrum of 2,4-dinitrotoluene (DNT) from 0.05 THz to 2.7 THz utilizing pulsed terahertz time-domain spectroscopy. We observed a broad-band absorption profile from 50 GHz to 600 GHz, peaking at 240 GHz. This broad absorption profile corresponds to DNTs pure rotational spectrum, which was confirmed by asymmetric top model calculations. Superimposed on the broad absorption profile, we observed discrete structure that extended to the higher THz frequencies. It is our contention that these features maybe related to the internal rotor motions of the NO2 and CH3 groups in DNT.