The band spectrum of silicon monosulphide and its relation to the band spectra of similar molecules

Abstract

In a recent paper (Jevons, Bashford and Briscoe 1937) on the ultraviolet band system of GeO, a survey was made of the band systems of the monoxides and monosulphides of the Group-IV(B) elements which appeared to be analogous to the “Fourth Positive” system (A 1 II -> x 1 Σ) of CO and the well-known ultra-violet systems of CS and SiO It was found that when the observed values of the vibrational coefficients w e and x e w e were plotted against the number of electrons in the molecule two pairs of uninflected curves were obtained for the lower states of the monoxides and monosulphides, these states being probably all 1 Σ ground states, and two similar pairs of curves were obtained for the upper states.