The transition frequencies were largely taken from
(1) M. Bogey, C. Demuynck, J. L. Destombes, and H. Dubus, 1987, J. Mol. Spectrosc. 122, 313.
Additional lines were published by
(2) S. Spezzano, F. Tamassia, S. Thorwirth, P. Thaddeus, C. A. Gottlieb, and M. C. McCarthy, 2012, Astrophys. J. Suppl. Ser. 200, Art. No. 1.
The uncertainties in (1) are overall somewhat conservative. Nevertheless, one line with large residual already in (1) has been omitted from the final fit. The parameter set is similar to that in (1), but Φ_KJ and Φ_JK were not used.
Predictions with uncertainties larger than 0.5 MHz should be viewed with caution.
The deuterium hyperfine splitting has been resolved to a large degree in (2).
The hyperfine splitting can also be resolved in astronomical observations of cold sources. Therefore, a separate hyperfine calculation is provided up to J = 3 and up to 60 GHz. The partition function values include the spin-multiplicity of the D nucleus.
Note: Non-trivial spin-statistics do not matter for this low symmetry (C_S) isotopolog.
The total dipole moment was taken from the main species, see e038506.cat. The large rotation of the inertial axis induces a sizable a-dipole moment component. The relative magnitude was derived in (2).