The experimental frequencies have been reported by
(1) M. E. Sanz, M. C. McCarthy, and P. Thaddeus, 2005, J. Chem. Phys. 122, Art. No. 194319.
ν₃ infrared transitions were also used in the fit. They were taken from
(2) K. M. T. Yamada, R. Schieder, G. Winnewisser, and A. W. Mantz, 1980, Z. Naturforsch. 35a, 690.
Predictions may be reliable up to 100 or even 200 GHz.
The dipole moment was assumed to agree with that of the ground vibrational state, see e051501.cat.
NOTE: The partion function does NOT take into account hyperfine splitting and refers to the ground state only ! Vibrational contributions to the partition function are available for selected states.