Identification of a non-assigned electronic system of the SiS radical

In 1938 a band system was observed by Barrow and Jevons and assigned by them to the SiS radical, but the nature of the two states involved remained unknown. Using high resolution spectra the authors have been able show that these bands represent the longer wavelength end of a well known system of SiS: the E 1 Sigma + -x 1 Sigma + transition.