A combined fit of several isotopic species and various vibrational states has been performed. Ground state lines of the main isotopolog were taken from
(1) S. K. Lee, H. Ozeki, and S. Saito, 1995, Astrophys. J. Suppl. Ser. 98, 351.
The stated uncertainties, with which the peak positions have been determined, are only a vague indication of the uncertainties of the transition frequencies, as is commonly found for data from that laboratory. With assumed uncertainties of 20 kHz for most of the lines, all but one line could be reproduced overall within the uncertainties. Excited state transitions were taken from
(2) J. R. Anacona, M. Bogey, P. B. Davies, C. Demuynck, J. L. Destombes, 1986, Mol. Phys. 59, 81.
Ground state transitions for the ³⁴S isotopolog were reported by
(3) F. J. Lovas, and R. D. Suenram, 1982, J. Mol. Spectrosc. 93, 416;
and by
(4) A. H. Saleck, H. Ozeki, and S. Saito, 1995, Chem. Phys. Lett. 244, 199.
One transition from (3) and two from (4) were omitted from the final fit. (4) also contained data for the ³³S and ¹⁵N isotopic species.
Infrared transitions were taken from
(5) A. Sinha, J. B. Burkholder, P. D. Hammer, C. J. Howard, 1988, J. Mol. Spectrosc. 130, 466.
A₀₀ and Y₂₀ were derived from data in
(6) A. Jenouvrier and B. Pascat, 1973, Can. J. Phys. 51, 2143.
Predictions in the ²Π_1/2 ladder should be reliable up to about 1000 GHz with the exception of J = 3/2 – 1/2 because of the uncertainties in the ³³S hyperfine parameters. Predictions for the higher lying ²Π_3/2 ladder should be viewed with great caution in particular because of the uncertainties in the ³³S hyperfine parameters.
The dipole moment was assumed to agree with that of the main isotopolog, see e046515.cat.