Dispersed fluorescence spectrum of the [formula omitted] vibronic transition

Abstract

The dispersed fluorescence spectrum following the excitation of HC 35 Cl A ̃ – X ̃ vibronic transition between 570 and 610 nm was successfully obtained in a direct current (DC) discharge supersonic free jet expansion. The analysis of the dispersed fluorescence spectrum results in detailed information of the HC 35 Cl X ̃ 1 A ′ state vibrational structure. The bending and C–Cl stretching frequencies as well as anharmonicity constants were determined for the first time. In addition, since no perturbation was observed in the vibrational structure of the X ̃ 1 A ′ state up to 2788 cm −1 , a lower limit of triplet–singlet energy gap was established to be roughly 8.0 kcal/mol.