The experimental data were taken from
(1) V. D. Gordon, M. C. McCarthy, A. J. Apponi, and P. Thaddeus, 2001, Astrophys. J. Suppl. Ser. 134, 311.
The reported uncertainties are slightly conservative and have been adjusted. Predictions beyond 35 GHz should be viewed with caution.
The dipole moment was estimated by
(2) H. S. P. Müller, 2018, unpublished.