Vibrational properties of molecule and crystal of TATB: A comparative density functional study

Vibrational properties of gas-phase TATB molecule and TATB crystal are investigated by means of density functional theory with gradient correction. The intramolecular geometry of TATB crystal agrees reasonably with experiment. The vibrational frequencies of TATB molecule and crystal are computed and the internal modes are analyzed. The simulated infrared spectra of the gas-phase TATB molecule reproduce the experimental spectra fairly well. The structure and vibrational properties of the TATB molecule in gas phase and in crystal phase are compared and discussed in terms of intermolecular interaction.