Infrared and Raman spectral data and conformations of 1-pentyne

The infrared spectra of 1-pentyne (CH3CH2CH2CCH) have been studied as a vapour and as a crystalline solid at 78K. Raman spectra of the liquid were recorded at 293K and polarization data were obtained. Additional Raman spectra of the liquid were recorded at various temperatures between 295 and 183K. Several Raman bands vanished in the low temperature solid at 160K, and both the IR and Raman spectra revealed that only one conformer was present in the crystal lattice.