The measurements were taken from
(1) H. Habara, S. Yamamoto, and T. Amano, 2002, J. Chem. Phys. 116, 9232.
The parameter set differs slightly from that in (1). Only K_a = 0 transitions have been observed in the laboratory so far. Therefore, the rotational constants are known only approximately. Transitions involving K_a = 1 cannot be calculated reliably predominantly because the size of ε_aa is not known. Moreover, since the barrier to linearity may be small it is conceivable that knowledge of the K_a = 1 energies will not help much in locating higher energy levels. Therefore, only transitions involving K_a = 0 are provided. The N = 17 – 16, J = 16.5 – 15.5 is somewhat uncertain because of electron spin-rotation interaction between K_a = 0 and 1. Nevertheless, the calculation may well be sufficient for all observational purposes. Transition frequencies with calculated uncertainties exceeding 0.1 MHz should be viewed with caution.
The partition function takes into account higher K_a values as far as possible at present.
The total dipole moment (1.02) is from an ab initio calculation from
(2) C. Ochsenfeld, R. I. Kaiser, Y. T. Lee, and M. Head-Gordon, 1999, J. Chem. Phys. 110, 9982.
An a dipole component of 0.4 D was communicated to the authors of a HSC article
(3) H. Habara and S. Yamamoto, 2000, J. Chem. Phys. 112, 10905.
The value should be slightly larger for DCS. In addition, there should be a b dipole component of about 0.9 D.