Dispersed fluorescence spectroscopy of the CBr2 Ã 1B1–1A1 transition

Abstract

Dispersed fluorescence spectra following the excitation of the CBr₂ Ã ¹B₁– ¹A₁ 2¹³₀ and 2¹⁴₀ bands at visible wavelengths were acquired in a discharge supersonic free jet expansion using an intensified charge-coupled device (ICCD) detector. The dispersed fluorescence spectra show signal-to-noise ratios of up to 60 and extend out to a maximum red shift frequency of 6000 cm⁻¹. Complete and detailed vibrational structure of the ground singlet state ( ¹A₁) was observed. Vibrational parameters including fundamental frequencies, anharmonicities, and coupling constants were determined for the CBr₂ ¹A₁ state. Additional vibrational structure starting at approximately 3650 cm⁻¹ was observed and this indicates the singlet–triplet energy gap to be >10 kcal mol⁻¹.