The Less Refrangible Bands in the Spectrum of Tin Monochloride

Four groups of bands previously obtained by Jevons in a discharge through SnCl₄ vapor are now found also in streaming active nitrogen. Two groups, α and β, were previously classified as a ²S→²P transition in SnCl; with the help of new measurements, and from an examination of the band structure, it is concluded that the other two groups, λ3500 and λ3800, are a ²D→²P transition with the same ²P state as the α and β bands. The chlorine isotope effect confirms the identity of the mitter as SnCl and confirms the vibrational quantum number assignments. The vibrational intensity distribution (intensity concentrated in Δn=0 sequence) is in qualitative agreement with theory, for the ratio of ω₀^'' to ω₀^'. An attempt was made to obtain analogous bands by introducing SnI₄ vapor into active nitrogen, but no new bands were obtained.