The first entry of Nov. 2001 was modified. The experimental lines were added from
(1) B. A. McGuire, M.-A. Martin-Drumel, K. L. K. Lee, J. F. Stanton, C. A. Gottlieb, and M. C. McCarthy 2018, Phys. Chem. Chem. Phys. 20, 13870.
These involve in particular very accurate low-N transition frequencies in the MW and lower mmW regions as well as remeasurements of two upper millimeter wave triplets. As earlier, millimeter data were taken from
(2) S. Saito, K. Kawaguchi, S. Yamamoto, M. Ohishi, H. Suzuki, and N. Kaifu, 1987, Astrophys. J. 317, L115.
Also retained are two MW lines from
(3) S. Yamamoto, 2001, unpublished.
These are the N_J = 1₂ – 2₁ and 2₃ – 1₂ lines at 22344.0308 and 33751.3696 MHz with an estimated experimental uncertainty of 1.0 kHz and in good agreement with data from (1).
Transition frequencies with calculated uncertainties exceeding 0.1 MHz should be viewed with some caution.
The dipole moment is from a quantum-chemical calculation from
(4) G. Pascoli, H. Lavendy, 1998, Int. J. Mass Spectrom. 181, 11;
its value should be viewed with some caution.