Journal of Chemical Physics, Vol.104, No.10, 3609-3619, 1996
A Detailed Study of the Predissociation Dynamics of the B-1(2)((1)Sigma(+)(U)) State of Cs2
The photodissociation dynamics of the B-1(2) state of CS2 have been studied for excitation energies between 46 600 and 50 500 cm(-1) (214-198 nm). These experiments used a tunable pulsed uv laser to photodissociate jet-cooled CS2 and the resulting atomic S products were detected by single photon VUV laser-induced fluorescence. These data allow for the measurement of the S(D-1(2)):S(P-3(J)) product branching ratios as a function of vibrational level in the B-1(2) state. Because of the low rotational temperature of the jet cooled CS2, we were able to resolve vibrational bands, and simulate the rotational contours for K = 0 and K = 1 vibrational bands up to 50 100 cm(-1) excitation energy, obtaining homogeneous linewidths for these levels. For vibrational levels close to the zero point, the dissociation dynamics, both lifetimes and product branching ratios, were very different for K = 0 and K = 1 levels at the same energy. In particular, K = 1 levels have shorter lifetimes, and a substantially higher yield of S(D-1(2)) product. We propose a model for the dissociation dynamics of the B-1(2) State of CS2, based on our results and preliminary ab initio calculations of the potential energy curves for excited states of CS2.
Keywords:ULTRAVIOLET-ABSORPTION SPECTRUM;193 NM;PHOTOFRAGMENT SPECTROSCOPY;PHOTODISSOCIATION;TRANSITION