Millimeter-wave spectrum of 2,3-difluorobenzonitrile and ab initio DFT calculations

The ground vibrational state rotational spectrum of 2,3-difluorobenzonitrile has been reinvestigated in the frequency range 40.0-99.0 GHz. High J and K−1 (J ⩽ 62 and K−1 ⩽ 20) transitions have been measured and analyzed to determine accurate rotational and centrifugal distortion constants. Finally, the experimental values were compared with the corresponding values computed at the DFT-B3PW91/6-31g(d,p) level of theory. A very good agreement has been found.