This entry is a combined CDMS and JPL entry.
The rotational transition frequencies were taken from
(1) B. J. Drouin, S. Yu, J. C. Pearson, and H. S. P. Müller 2009, J. Quant. Spectrosc. Radiat. Transfer 110, 2077.
In addition, infrared ground state combination differences were used in the fit. These were published in
(3) C. Chackerian, Jr., and G. Guelachvili, 1980, J. Mol. Spectrosc. 88, 244.
Additional spectroscopic parameters were taken from the ¹²C species, see e017503.cat.
Predictions with uncertainties larger than 1 MHz should be viewed with some caution.
At low temperatures, it may be necessary to discern between A-¹³CH₃D and E-¹³CH₃D. The A state levels are described by K = 3n, those of E state by K = 3n ± 1. The nuclear spin-weight ratio is 2 : 1 for A-¹³CH₃D with K > 0 and all other states, respectively. The J_K = 1₁ level is the lowest E state level. It is 9.1240 cm^–1 above ground.
The dipole moment and distortion corrections were assumed to agree with the ¹²C species, see e017503.cat.
As the distortion effects are rather large the intensities should be viewed with increasing caution beyond J of about 8.