One laboratory line was reported by
(1) P. B. Changala, H. Gupta, J. Cernicharo, J. R. Pardo, M. Agúndez, C. Cabezas, B. Tercero, M. Guélin, and M. C. McCarthy, 2022, Astrophys. J. Lett. 940, Art. No. L42.
Except for (B + C)/2, parameters were kept fixed to scaled or unscaled parameters from
(2) A. G. Watrous and R. C. Fortenberry, 2023, unpublished,
based on their work in
2023, Mon. Not. R. Astron. Soc. 518, 5140.
Transition frequencies with K_a = 0 may be quite reliable; all others were omitted because of too great uncertainties.
The dipole moment of the main isotopic species was taken from a quantum-chemical calculation in
(3) S. Itono, K. Takano, T. Hirano, and U. Nagashima, 2000, Astrophys. J. 538, L163;
the value in 3 agree with this value.