The transition frequencies have been reevaluated once more with respect to earlier entries from Sep. 2014, Apr. 2009, and Aug. 2008. Details are given in
(1) S. Muller, H. S. P. Müller, J. H. Black, M. Gérin, F. Combes, S. Curran, E. Falgarone, M. Guélin, C. Henkel, S. Martín, K. M. Menten, E. Roueff, S. Aalto, A. Beelen, T. Wiklind, and M. A. Zwaan, 2017, Astron. Astrophys. 606, Art. No. A109.
New N = 1 – 0 transition frequencies, except one, were taken from
(2) D. T. Halfen and L. M. Ziurys, 2015, Astrophys. J. 814, Art. No. 119;
see (1) for details; the correct transition frequency was estimated there. Additional, albeit redundant and less accurate frequency information was taken from
(3) C. Savage, A. J. Apponi, and L. M. Ziurys, 2004, Astrophys. J. 608, L73;
and from
(4) H. S. P. Müller, J. R. Goicoechea, J. Cernicharo, M. Agúndez, J. Pety, S. Cuadrado, M. Gerin, G. Dumas, and E. Chapillon, 2014, Astron. Astrophys. 569, Art. No. L5.
In addition, extrapolated zero-field transition frequencies from
(5) J. M. Brown and H. S. P. Müller, 2009, J. Mol. Spectrosc. 255, 68
were used in the fit. These were derived from laser magnetic resonance measurements in
(6) D. C. Hovde and R. J. Saykally, 1987, J. Chem. Phys. 87, 4332.
Also used in the fit were infrared transition frequencies up to v = 2 – 1 and 4 – 3, respectively, from
(7) P. R. Brown, P. B. Davies, and S. A. Johnson, 1986, Chem. Phys. Lett. 132, 582;
and from
(8) S. Civiš, C. E. Blom, and P. Jensen, 1989, J. Mol. Spectrosc. 138, 69.
Predictions with uncertainties exceeding 0.3 MHz should be viewed with some caution. Predictions with uncertainties exceeding 3 MHz or with ΔJ ≠ ΔN should be viewed with greater caution.
The dipole moment is from an ab initio calculation from
(9) J. Senekowitsch, H.-J. Werner, P. Rosmus, E.-A. Reinsch, and S. V. O'Neil, 1985, J. Chem. Phys. 83, 4661.