The emission spectrum of iodine bromide excited in the presence of argon. Part I. The band system in the regions 5425-5360 Å, 4520-4415 Å and 4120-4010 Å

Abstract

IBr vapour was excited in the presence of argon by an uncondensed transformer discharge. Four band systems were obtained in the regions 5425-5360 Å, 4520-4415 Å, 4120-4010 Å and 3915-3540 Å of which the first three are discussed in this paper. The wavelengths and wavenumbers of the band heads in three systems as measured from the plates obtained with a 3-prism Steinheil glass spectrograph are given along with their visually estimated relative intensities. The three band systems, which are new, are analysed and the following vibrational constants expressed in cm.⁻¹ are obtained:Band system v _e w _e " w _e "x _e " w _e "y _e " w _e ' w _e 'x _e ' 5425-5360 Å 18613 65·5 0·24 -0·01 43·0 0·026 4520-4415 Å 22312 65·5 0·24 -0·01 77·0 0·5 4120-4010 Å 24540 160·6 1·125 .. 128·4 0·1 The lower state of the first two systems has been identified with the (O⁺) state at 16814 cm.⁻¹ reported earlier by Brown from a study of the absorption bands in the visible region.