The first measurements of the depolarization ratios for low frequency Raman active rotational and translational modes of semicrystalline (melt) pyrazinamide (PA) are reported. Tentative assignments have been proposed for the lattice modes based on polarization characteristics and their experimental intensities. Intra- and inter-translational oscillations have been assigned using an isolated single-chain approximation whereas the rotational oscillations are identified by their intensities and energy-order in similar NH…N hydrogen bond system. The PA dimer symmetry based on these results has been discussed and supports the planar conformation.
