Vibrational assignments and thermodynamic properties of triclinic TATB

We have used the first-principles density-functional theory calculations to study the structural parameters, Raman/IR spectrum, electronic, vibrational, dielectric, thermodynamic and optical properties of TATB. The obtained structural parameters and the vibrational frequencies of the internal modes are consistent with previous results. The results of density of states, bond populations and Mulliken charges are used to analyze the electronic properties and chemical bondings. The vibrational frequencies (in 300-3267 cm−1) are assigned to corresponding vibrational modes. We also used the phonon density of states and quasiharmonic approximation to calculate entropy, enthalpy, heat capacity and Gibbs free energy. Further, the permittivity, refractive index, reflectivity, absorption coefficient, loss function and optical conductivity have been obtained.