The entry is a modification of the second entry from Sep. 2005. The main change is a significantly larger dipole moment because of mixing between the two lowest electronic states. The value is much better than the ealier one, but should be taken with some caution. The millimeter wave transitions without D hyperfine splitting ave been reported by
(1) D. R. Woodward, J. C. Pearson, C. A. Gottlieb, and P. Thaddeus, 1988, Astrophys. J. 333, L29.
With respect to the Sep. 2000 entry, microwave transitions with D hyperfine splitting have been included in the fit. They were reported by
(2) E. Kim and S. Yamamoto, 2005, J. Mol. Spectrosc. 233, 93.
Transition frequencies with calculated uncertainties exceeding 0.2 MHz should be viewed with caution.
Deuterium hyperfine splitting is observable at low temperatures and low frequencies. Therefore, predictions with hyperfine splitting are available for the lowest values of N. The partition function considers the D hyperfine splitting, but no excited vibrational states.
The dipole moment was assumed to be the same as for the main isotopolog, see e049503.cat.