DFT, FT-Raman and FT-IR investigations of 5-o-tolyl-2-pentene

► The FT-IR and FT-Raman spectra of 5-o-tolyl-2-pentene (OTP). ► Geometric isomers of OTP. ► DFT/B3LYP level is able to provide satisfactory results for predicting vibrational wavenumbers. ► The trans isomer is supposed to be the most stable form of OTP molecule.