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 st udied for excitation energies between 46 600 and 50 500 cm(-1) (214-19 8 nm). These experiments used a tunable pulsed uv laser to photodissoc iate 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 l ow rotational temperature of the jet cooled CS2, we were able to resol ve vibrational bands, and simulate the rotational contours for K = 0 a nd K = 1 vibrational bands up to 50 100 cm(-1) excitation energy, obta ining 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 lev els at the same energy. In particular, K = 1 levels have shorter lifet imes, and a substantially higher yield of S(D-1(2)) product. We propos e a model for the dissociation dynamics of the B-1(2) State of CS2, ba sed on our results and preliminary ab initio calculations of the poten tial energy curves for excited states of CS2. (C) 1996 American Instit ute of Physics.