The high resolution infrared spectrum of the v4 band of 1,1,1-trifluoroethane

The v4 band of 1,1,1-trifluoroethane (CH3CF3) has been studied using synchrotron radiation at the far-infrared beamline, Canadian Light Source. The spectra were recorded at a resolution of 0.00096 cm-1 in the spectral range 800 to 860 cm-1 using a Bruker IFS125 FT spectrometer. Altogether 2785 lines were assigned to qPK(J) and qRK(J) transitions with J '' up to 71 and K up to 45. The qQK(J) sub-branches are too congested and overlapped to other hot-band Q branches to be analysed. A Watson-type Hamiltonian containing the usual terms up to the 6th power in the angular momentum operators was used in the analysis. The spectroscopic parameters obtained from the fit reproduce 2636 transitions with a standard deviation of about 0.00016 cm-1.