Time resolved detection of the S(1D) product of the UV induced dissociation of CS2.

ABSTRACT

The products formed following the photodissociation of UV (200 nm) excited CS2 are monitored in a time resolved photoelectron spectroscopy experiment using femtosecond XUV (21.5 eV) photons. By spectrally resolving the electrons, we identify separate photoelectron bands related to the CS2 + hν → S(1D) + CS and CS2 + hν → S(3P) + CS dissociation channels, which show different appearance and rise times. The measurements show that there is no delay in the appearance of the S(1D) product contrary to the results of Horio et al. [J. Chem. Phys. 147, 013932 (2017)]. Analysis of the photoelectron yield associated with the atomic products allows us to obtain a S(3P)/S(1D) branching ratio and the rate constants associated with dissociation and intersystem crossing rather than the effective lifetime observed through the measurement of excited state populations alone.