Electronic spectroscopy of bromomethylenes in a supersonic free jet expansion

Laser excitation and dispersed fluorescence spectra of bromomethylenes (CBr₂ and HCBr) between 546 and 576 nm have been recorded following their production in a plasma discharge in a supersonic free jet expansion. The analyses of the excitation and dispersed fluorescence spectra reveal several new vibrational levels of the CBr₂ Ã state as well as the detailed vibrational structure of the X̃ state. In addition, a new Ã-X̃ band of HCBr was found in the excitation spectrum and the dispersed fluorescence spectrum following the excitation of this new HCBr band has also been recorded. The complete vibrational structure of the HCBr X̃¹A′ state including the previously unknown C-H stretch fundamental frequency was determined for the first time and the rotational constants for three HCBr bands at visible wavelengths were also determined for the first time.