The emission spectrum of IBr excited in the presence of argon. Part II. The band system in the region 3915-3540 Å

Abstract

Wavelengths and wavenumbers of the band heads in the region 3915-3540 Å are recorded as obtained from the measurements of the plates taken on a first order 21-feet grating spectrograph. Earlier workers recently reported 40 bands of this system covering the region 3900-3800 Å . All the bands of this system obtained in the present experiments are analysed as involving the³ ∏ (1) state for lower state. The constants for the lower state are such that they represent well the Δ G (v+1/2) values obtained in the present experiments fromv=0 tov=26 as well as those obtained by Brown fromv=9 tov=43. The vibrational constants of the two states involved are: w"_e 137·8 cm. ⁻¹ , w"_e x"_e 0·571 cm. ⁻¹ w"_e y"_e - 0·1156 cm. ⁻¹ w"_e z"_e 3·09 ×10 ^{- 3} cm.⁻¹ w"_e t_e - 2·5 ×10 ⁻⁵ cm.⁻¹ , w"_e 90·1 cm. ⁻¹ , w"_ex"_e 0·15 cm. −1 The probable electronic configurations and electronic terms for the different observed states of IBr are discussed.