Experimental study of the DCCl X̃1A′ state vibrational structure by dispersed fluorescence spectroscopy

Abstract

Dispersed fluorescence spectra following excitation of the DCCl Ã-X̃ vibronic bands between 570 and 620 nm were successfully recorded for the first time using a combination of direct current discharge and supersonic free jet expansion techniques to produce the radical. This is the first experimental study on the DCCl X̃1A′ state vibrational structure. Analysis of the dispersed fluorescence spectra reveals details of the vibrational structure of the DCCl X̃1A′ state. Emission bands to all three vibrational modes were observed and the fundamental vibrational frequencies were determined: 2078 cm−1 (C–D stretch), 893 cm−1 (bend), and 801 cm−1 (C–Cl stretch). Vibrational parameters including anharmonicities and the bend-stretch coupling constant for the DCCl X̃1A′ state were also determined using a least-square fit. In addition, based on our results, the triplet-singlet energy gap (the zero-point level energy gap) could be estimated to be approximately 11±2 kcal/mol.