The rotational analysis of some bands of the near ultra-violet system (D-X) of silicon monosulphide

A rotational analysis has been done of the 0,1, 0,2, 0,3, 0,4, and 1,5 bands of the near ultra-violet band-system (ν e ≃ 35030 cm. -1 ) of SiS. The transition responsible for the production of the band-system is of the type D 1 Π - X 1 Σ. The rotational constants have been derived from two sets of experimental observations: (1) of the bands in absorption, by G. Herzberg, N. Olson and F. J. Wilson (University of Saskatchewan), and (ii) of the bands in emission, by the author. The more important constants are given by B ν '' = 0.3036 - 0.0014 9 (ν'' + ½), for the ground state, and B ν ' = 0.2664 - 0.0020 5 (ν' + ½) for the upper state. Λ-type doubling in the upper 1 Π state is negligibly small, at least up to J = 100. The values of the equilibrium internuclear distances are r e '' = 1.929 Å. and r e ' = 2.059 5 Å. A brief discussion of the results is given.