Vibrations of polythiophenes

► We study vibrational properties of polythiophenes up to 12mer by DFT calculations. ► The analysis includes odd-sized oligomers, treated only sporadically so far. ► The agreement with the experiments is improved as compared to other publications. ► The B3LYP functional reproduces better the low-frequency out-of-plane vibrations. ► The PBE functional reproduces better the high-frequency in-plane vibrations.