Vibrational spectrum of 1,1,1-trifluoroethane

Abstract

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.