The experimental frequencies have been reported by
(1) K. M. T. Yamada, R. Schieder, G. Winnewisser, and A. W. Mantz, 1980, Z. Naturforsch. 35a, 690.
v₃ = 1 rotational transitions were also used in the fit. They were taken from
(2) M. E. Sanz, M. C. McCarthy, and P. Thaddeus, 2005, J. Chem. Phys. 122, Art.-No. 194319.
Predictions may be reliable up to J = 85. The absolute accuracy of the IR transitions was estimated to be better than 0.005 cm^–1, the precision is about 0.002 cm^–1.
The transition dipole moment was derived from intensity measurements by
(3) A. Jolly, Y. Benilan, and A. Fayt, 2007, J. Mol. Spectrosc. 242, 46.
NOTE: The partion function refers to the ground state only ! Vibrational contributions to the partition function are available for selected states.