The microwave frequencies have been reported by
(1) C. C. Costain and R. J. Morton, 1959, J. Chem. Phys. 31, 389.
The millimeter wave frequencies have been reported by
(2) G. Winnewisser 1973, J. Mol. Spectrosc. 46, 16.
Additional ground state combination differences have been provided by A. R. W. McKellar. They were obtained from
(3) A. R. W. McKellar, J. K. G. Watson, L.-K. Chu, Y.-P. Lee, 2008, J. Mol. Spectrosc. 252, 230.
Predictions with uncertainties larger than 1 MHz should be viewed with caution.
The dipole moment was reported in
(4) R. D. Brown and P. D. Godfrey, 1984, Aust. J. Chem. 37, 1951.