“…The measurements of Mallinson [8] between 26.5 and 40 GHz permitted the determination of the three rotational constants and the five quartic centrifugal distortion constants. More recently, an international group of researchers [9] have combined microwave Fourier transform, millimeterwave and submillimeterwave spectroscopy and determined improved set of rotational and centrifugal distortion constants (up to sextic terms) together with iodine quadrupole coupling constants. In that work, to obtain more accurate results, they also used the ground state combination differences from the spectrum studied in Ref.…”