Vibrational spectrum of 1,1,1-trifluoroethane

IR spectra of 1,1,1-trifluoroethane (HFC-143a) have been recorded at medium and high resolution. Raman spectra in polarization controlled experiments have also been measured. Comparison between the spectra recorded with the two techniques has made possible a reassignment of the vibrational spectrum of CH3CF3 in the range 200–3100 cm-1. Room-temperature and low-temperature gas-phase spectra were compared in order to assign a large number of hot bands due to the low lying fundamentals ν6 (A2, ca. 220 cm-1) and ν12 (E, 366cm-1). An unambiguous assignment for ν8 has been obtained, together with a reliable frequency for ν6, which is forbidden in both the IR and Raman.