The spectroscopic parameters and the experimental transition frequencies were published in
(1) H. S. P. Müller, A. Belloche, K. M. Menten, C. Comito, and P. Schilke, 2008, J. Mol. Spectrosc. 251 319.
Besides from this work, the data originate from
(2) J. M. Colmont, G. Wlodarczak, D. Priem, H. S. P. Müller, E. H. Tien, R. J. Richards, and M. C. L. Gerry, 1997, J. Mol. Spectrosc. 181, 330.
Data with experimental uncertainties larger than 50 kHz have not been merged.
Predictions with uncertainties exceeding about 1 MHz should be viewed with increasing caution.
NOTE: Energy levels up to J = 170 and K_a = 50 have been considered in the calculation of the partition function. This is sufficient up to 300 K. At higher temperatures classical extrapolations are recommended. The partition function does not include contributions from low-lying vibrational modes. Estimates for these corrections are available for the main isotopic species, see e053515.cat.
The dipole moment was assumed to agree with that of the main isotopic species, see e053515.cat.