The experimental millimeter and lower submillimeter lines are from
(1) M. A. Martin-Drumel, J. van Wijngaarden, O. Zingsheim, F. Lewen, M. E. Harding, S. Schlemmer, and S. Thorwirth, 2015, J. Mol. Spectrosc. 307, 33.
Additional longer wavelength data were taken from
(2) F. J. Lovas, E. Tiemann, and D. R. Johnson, 1974, J. Chem. Phys. 60, 5005;
and from
(3) S. Thorwirth, P. Theulé, C. A. Gottlieb, H. S. P. Müller, M. C. McCarthy, and P. Thaddeus, 2006, J. Mol. Struct. 795, 219.
Predictions should be viewed with some caution once the calculated uncertainties excced 500 kHz.
The dipole moment is from (2).