Dispersed fluorescence spectrum of the HC35ClÖX̃ vibronic transition

The dispersed fluorescence spectrum following the excitation of HC35Cl ÖX̃ 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 HC35Cl X̃1A′ 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 X̃1A′ state up to 2788 cm−1, a lower limit of triplet–singlet energy gap was established to be roughly 8.0 kcal/mol.