Further rotational spectroscopy of phenol: Sextic centrifugal distortion and vibrational satellites

The room temperature rotational spectrum of phenol has been reinvestigated at 8–18 GHz with a waveguide Fourier transform microwave spectrometer and at 90–137 GHz with a harmonic generation spectrometer. The supersonic expansion spectrum was also measured at 9–18 GHz with a cavity Fourier transform microwave spectrometer. The data sets for the ground state and the two lowest excited vibrational states have been considerably extended, resulting in significant improvement of the spectroscopic parameters. In particular, access to different transition types facilitated by the waveguide spectrometer allowed precise determination of sextic centrifugal distortion constants for the ground state and their intercomparison with computed values. Transitions in the next five higher vibrational states have been assigned and fitted for the first time, and the vibrational assignment was confirmed by computed inertial defects and vibrational changes in rotational constants.