The experimental frequencies have been reported by
(1) P. D. Mallinson and R. L. de Zafra, 1978, Mol. Phys. 36, 827; by
(2) S. Thorwirth, H. S. P. Müller, and G. Winnewisser, 2001, Phys. Chem. Chem. Phys. 3, 1236; and by
(3) A. Fayt, C. Vigouroux, F. Willaert, L. Margules, L. F. Constantin, J. Demaison, G. Pawelke, E. B. Mkadmi, and H. Bürger, 2004, J. Mol. Spectrosc. 695–696, 295.
Direct-l-type transitions were also employed in the fit. These were reported in
(4) J. Haekel and H. Mäder, 1988, Z. Naturforsch. 43a, 1111.
Below 500 GHz, transitions with uncertainties ≥ 50 kHz have not been merged. The prediction has been truncated at J" = 99 even though the measurements in (3) extend to slightly higher quantum numbers.
Note: The partition function does not include vibrational contributions. However, information on vibrational contributions to the partition function is available.
The dipole moment was assumed to be the same as for the main species, v₇ = 1, see e051502.cat.