Etude des spectres i.r. et Raman du butyne-1 et de sept composés analogues deutériés

The i.r. and Raman spectra of eight 1-butynes: CH3CH2CCH, CH3CH2CCD, CH3CD2CCH, CH3CD2CCD, CD3CH2CCD, CD3CH2CCD, and CD3CD2CCD have been measured. From a comparative analysis of the spectra, together with those of other related molecules, all the fundamental vibrations, with the exception of the torsional vibration of the methyl group, have been assigned for each of the eight molecules. The splitting of the degeneracy of the CCH bend into two frequencies is discussed. The fundamental δ(CCD) is found to exhibit coupling with an A′ skeletal deformation mode while γ(CCD) is assigned to a Q branch at a constant wavenumber (494 cm−1) in the i.r. spectrum of the studied RCCD compounds.