Emission spectrum of bromine excited in the presence of argon. Part I

Abstract

Bromine was excited by an uncondensed transformer discharge in the presence of argon. The spectrum obtained was found to be different from what one gets without the presence of a foreign gas and consists of (1) a short discrete band system in the region 3150-2970 Å , (2) an extensive discrete band system in the region 2950-2670 Å , (3) a short and weak discrete system in the region 2660-2590 Å and a set of diffuse bands in the region 3340-3190 Å . The wavelengths and wave numbers of the band heads of the system 2950-2670 Å , as obtained from the measurements of the plates taken on the first order 21-ft. grating spectrograph, are given along with the vibrational analysis. This system is shown to be due to a transition from an upper electronic state at 51802 cm.⁻¹ with ω '_e = 150·5 cm.⁻¹ and ω '_e X'_e = 1·15 cm.⁻¹ to the well known³ ∏ _a (O₂ ⁺) state at 15918 cm.⁻¹