The v = 0 and v₂ = 1 data have been fit together. In contrast to the Dec. 2000 entry, now two entries are given, one for each state. Moreover, a different frequency was used for the v = 0, J = 1 – 0 transition. Therefore, the v = 0 entry has a new version number. Besides J as the first quantum number, the l value and a vibrational identifier are the second and third quantum number, respectively.
The v = 0, J" = 0 transition was taken from
(1) R. J. Saykally, P. G. Szanto, T. G. Anderson, and R. C. Woods, 1976, Astrophys. J. 204, L143;
the v = 0, J" = 1 transition was taken from
(2) R. A. Creswell, E. F. Pearson, M. Winnewisser, and G. Winnewisser, 1976, Z. Naturforsch. A 31, 221;
the J" = 2 and 3 transitions were from
(3) T. Okabayashi and M. Tanimoto, 1993, J. Chem. Phys. 99, 3268;
the remaining transitions up to 2 THz were published by
(4) S. Thorwirth, H. S. P. Müller, R. Gendriesch, F. Lewen, and G. Winnewisser, 2000, Astron. Astrophys. 363, L37.
Also employed in the fit were rovibrational transitions from
(5) J. B. Burkholder, A. Sinha, P. D. Hammer, C. J. Howard, 1987, J. Mol. Spectrosc. 126, 72; and from
(6) A. G. Maki and G. Ch. Mellau, 2001, J. Mol. Spectrosc. 206, 47.
The partition function takes into account both vibrational states. Individual contributions of the vibrational states to the partition function are available.
The dipole moment was reported by
(6) G. L. Blackman, R. D. Brown, P. D. Godrey, and H. I Gunn, 1976, Nature 261, 395.
It was assumed to be equal for both states.