Temperature-dependent Raman spectra of triaminotrinitrobenzene: Anharmonic mode couplings in an energetic material

The temperature-dependent Raman spectrum of triaminotrinitrobenzene (TATB) is examined to determine phonon-molecular vibrational coupling information. Spectra are reported from 4-295 K over a spectral range 50-3350 cm(-1). The 4 K TATB spectrum allows far greater resolution than at room temperature, with sharp phonon peaks prominent. The temperature dependence in TATB is fit very well by standard perturbation theoretical expressions for cubic (peak broadening) and quartic (peak frequency shift) anharmonicities, and averaged mode coupling information can thus be obtained. Confident assignments of specific mode coupling constants are not possible due to the large number of potentially interacting vibrations. However, these data on the entire spectrum across the broad range of temperatures provide experimental constraints useful for testing models of vibrational energy transfer in TATB. Possible relations of this study to shock initiation are briefly discussed. (C) 2003 American Institute of Physics.