The experimental data were reported by
(1) F. Müller and A. Bauder, 1996, J. Mol. Spectrosc., 179, 61;
and by
(2) M. Behnke, I. Medvedev, M. Winnewisser, F. C. De Lucia, and E. Herbst, 2004, Astrophys. J. Suppl. Ser., 152, 97.
Predictions should be sufficiently accurate for all observational purposes. They should be viewed with caution if calculated uncertainties exceed 0.2 MHz.
The dipole moment components were determined in (1).