The microwave data were contributed by
(1) D. Damiani, L. Ferretti, and E. Gallinella, 1976, Chem. Phys. Lett. 37, 265.
Estimates of the quartic distortion parameters were derived from an MP2 quantum-chemical calculation by
(2) H. S. P. Müller, 2021, unpublished;
following
(3) H. S. P. Müller, A. Brahmi M., J.-C. Guillemin, F. Lewen, and S. Schlemmer, 2021, Astron. Astrophys. 647, Art. No. A179.
The data set is very small, but the calculations may be sufficient for searches in cold sources. Transition frequencies with J ≥ 10 should be taken with caution as should those with calculated uncertainties exceeding 0.1 MHz.
Non-trivial spin-statistics do not matter for this isotopolog.
The total dipole moment was assumed to agree with that of the main isotopolog; the relative magnitudes were taken from (2). The a-component should be taken with some caution.