Photofragment spectroscopy of CS2 at 193 nm: Direct resolution of singlet and triplet channels

Abstract

The 193 nm dissociation of CS2 has been studied under supersonic molecular beam conditions, with the atomic S products detected by vacuum ultraviolet laser-induced fluorescence. These experiments measure the branching ratio between singlet and triplet channels to be S(3P)/S(1D) =2.8±0.3. Doppler spectroscopy on the S(3P2) and S(1D2) products was used to study the dynamics of each channel separately. The energy release in each channel was similar, with the CS fragments formed vibrationally inverted with about 50% of the available energy in CS rotation and vibration. The recoil velocity anisotropy in each channel was also measured, found to be the same for both, and was consistent with a 2 ps lifetime for the 1Σ+u(1B2) excited state of CS2.