Ultrafast Extreme Ultraviolet Photoelectron Spectroscopy of Nonadiabatic Photodissociation of CS2 from 1B2 (1Σu+) State: Product Formation via an Intermediate Electronic State

We studied nonadiabatic dissociation of CS2 from the B-1(2) ((1)Sigma(+)(u)) state using ultrafast extreme ultraviolet photoelectron spectroscopy. A deep UV (200 nm) laser using the filamentation four-wave mixing method and an extreme UV (21.7 eV) laser using the high-order harmonic generation method were employed to achieve the pump-probe laser cross-correlation time of 48 fs. Spectra measured with a high signal-to-noise ratio revealed clear dynamical features of vibrational wave packet motion in the B-1(2) state; its electronic decay to lower electronic state(s) within 630 fs; and dissociation into S(D-1(2)), S(P-3(J)), and CS fragments within 300 fs. The results suggest that both singlet and triplet dissociation occur via intermediate electronic state(s) produced by electronic relaxation from the B-1(2) ((1)Sigma(+)(u)) state.

Automated summary

The nonadiabatic dissociation of CS2 from the B-1(2) state was studied using ultrafast extreme ultraviolet photoelectron spectroscopy. The results revealed vibrational wave packet motion, electronic decay, and dissociation into S and CS fragments. Singlet and triplet dissociation occur via intermediate electronic state(s) produced by electronic relaxation from the B-1(2) state.