Chirped-pulse Fourier transform microwave spectroscopy of perfluoroiodoethane

The pure rotational spectrum of perfluoroiodoethane between 8.0 and 11.9 GHz has been measured on a search accelerated, correct intensity Fourier transform microwave (SACI-FTMW) spectrometer. The spectra is dense with 247 measured transitions in the given region. Only the anti   conformer was observed for which rotational constants are reported. Nuclear electric quadrupole coupling constants due to the iodine-127 were determined and are reported. Also, two dipole forbidden/quadrupole allowed ΔJ=2ΔJ=2 transitions were observed in the spectra. The observation of these transitions has been rationalized on the basis of near degeneracies between energy levels connected by χabχab.