The experimental lines are from
(1) R. D. Brown, K. G. Dyall, P. D. Godfrey, P. C. Elmes, and D. Mc Naughton, 1988, J. Am. Chem. Soc. 110, 789.
Some spectroscopic parameters were estimated from the main isotopolog by
(2) H. S. P. Müller, 2002, unpublished.
The calculations should be accurate enough for observations in cold sources. K_a = 0 and 1 may be reliable enough up to the 3 mm region. Transitions involving higher K_a should be viewed with increasing caution.
At low temperatures, it may be necessary to discern between ortho-H₂C₃³⁴S and para-H₂C₃³⁴S. The ortho states are described by K_a odd, the para states by K_a even. The nuclear spin-weights are 3 and 1 for ortho-H₂C₃³⁴S and para-H₂C₃³⁴S, respectively. The J_KaKc = 1₁₁ level is the lowest ortho level. It is approximately 9.6 cm^–1 above ground.
The dipole moment was taken from the main isotopolog.