Dynamics of the O(P-3)+cS(2)(X1 Sigma(+)(g))-> SO(X-3 Sigma(-))+CS(X-1 Sigma(+)) reaction

The rovibrational state distributions of both the CS and the SO products fo llowing the reaction of O(P-3) + CS2 have been investigated. The O(P-3) ato ms are generated by photolysis of NO:! using a frequency-tripled Nd:YAG las er at 355 nm. The SO(X(3)Sigma (-), upsilon" = 0-6) and CS(X(1)Sigma (+), u psilon" = 0-3) are observed directly using laser induced fluorescence (LIF) spectroscopy on the (B(3)Sigma (-) - X(3)Sigma (-)) and (A(1)II - X(1)Sigm a (+)) transitions, respectively. The SO(X(3)Sigma (-)) product is found to be highly excited with the vibrational state distribution inverted at upsi lon" = 1 and detectable population up to upsilon" = 6, while the CS(X(1)Sig ma (+)) product vibrational state distribution is characterized as Boltzman n with a vibrational temperature of 1230 +/- 155 K. The total vibrational e xcitation of both products accounts for 21% of the available energy to the products. The near nascent SO(X(3)Sigma (-), upsilon" 0-4) rotational state distributions are characterized by rotational temperatures in the range of 882-1312 K, and the near nascent CS(X(3)Sigma (+), upsilon" = 0) is charac terized by a temperature of 2986 +/- 607 K. The total rotational energy of the products accounts for 34.8% of the available energy. Correlated ah init io calculations of the reaction pathway have been performed, resulting in a ccurate energies for the reactants, products, intermediates, and transition states. Optimized geometries for the intermediates and transition states h ave been obtained. The inverted vibrational state distribution of the SO(X( 3)Sigma (-)) product and the excited rotational state distribution of the C S(X(1)Sigma (+)) product suggest a short-lived, nonlinear intermediate stru cture as the primary pathway for the reaction. The results from the ab init io calculations corroborate this model.