Product state resolved stereodynamics of the reaction H(~2S) + CO_2 → OH(X~2Π_(3/2); v = 0, N = 5) + CO(~1Σ~+)

摘要

The detailed stereodynamics of the H + CO_2 system have been studied using polarized Doppler resolved laser induced fluorescence to state selectively probe the OH product. The lambda-doublet specific differential cross-sections and translational energy distributions were measured, along with the scattering angle dependence of the rotational angular momentum polarization. The observed centre-of-mass differential cross-section has significant contributions in both the forward and backward hemispheres, with a small preference for backward scattering, and the measured fraction of available energy released as translational energy is greater than that predicted by statistical models. The rotational angular mometum vector of the OH product displays a polarized angular distribution, measured with respect to the reagent relative velocity vector k and the kk′ scattering plane, with the π(A ″) lambda-doublet component being significantly more strongly polarized than the π(A′ ) level. In addition, those products scattered backwards are seen to have a different polarization from those scattered forwards. The unprecedented detail of the information obtained is explained in terms of rather stringent steric constraints in the entrance channel and the formation of short-lived collision complexes.