화학공학소재연구정보센터
Journal of Chemical Physics, Vol.100, No.7, 4925-4931, 1994
Co(V,J) Product State Distributions from the Reaction O(3P)+ocs-)Co+so
The title reaction was studied by probing CO[upsilon,J] product state distributions with a tunable infrared diode laser. Only the fastest O(3P) atoms formed by 355 nm photolysis of NO2, i.e., Those corresponding to NO[2PI1/2, upsilon = 0], have sufficient energy to surmount the activation barrier. Thus these experiments were performed under monoenergetic, near-threshold conditions. The CO[upsilon,J] distributions were extracted from the relative slopes of the transient infrared absorption signals. Little vibrational excitation is observed. The vibrational branching ratio is [upsilon=1]/[upsilon=0]almost-equal-to 0.05; CO[upsilon greater-than-or-equal-to 21 was not detected. In contrast, rotational degrees of freedom are much hotter. The nascent CO[upsilon = 0] rotational distribution is well characterized by a temperature of T(R)=4400+/-390 K. Total CO internal excitation, on the average 3150 cm-1, accounts for 16% of the energy available to products. Surprisal analyses based on several models of energy disposal show that the nascent distributions are nonstatistically cold. The results are consistent with direct attack at the S atom to firm an OSCO intermediate, followed by rapid C-S bond scission which exerts a torque on the CO product.