Normal Vibrations of Trinitro Toluene: Need for a Fresh Study

In view of certain infirmities in the available data on the normal coordinate analysis of TNT, a fresh study from the both theoretical and experimental viewpoints has been necessitated. Wilson's GF matrix method with Urey-Bradley force field has been used to calculate normal frequencies. Valence charge distribution using INDO/MO calculations lend support to the force field used. The experimental data have been obtained from the Fourier transform infrared absorption spectra. This spectrum is a superposition of the two types of molecular structures present in TNT. The changed valence charge distribution in trinitrobenzene on the introduction of the methyl group is indicated as a possible reason for the explosive nature of TNT.