Internal Energy Distributions of OH Products in the Reaction of O(3PJ) with HSiCl3

The OH(X2Π, υ"=0, 1) internal state distributions from the reaction of electronically ground state oxygen atoms with HSiCl3 were measured using laser-induced fluorescence. The ground-state O(3PJ) atoms with kinetic energies above the reaction barrier were produced by photolysis of NO2 at 355 nm. The OH product revealed strong vibrational population inversion, P(υ"=1)/P(υ"=0) = 4.0 ± 0.6, and rotational distributions in both vibrational states exhibit substantial rotational excitations to the limit of total available energy. However, no preferential populations in either of the two Λ doublet states were observed from the micropopulations, which supports a mechanism involving a direct abstraction of hydrogen by the atomic oxygen. It was also found that the collision energy between O and HSiCl3 is effectively coupled into the excitation of the internal degrees of freedom of the OH product ( = 0.62, and < frot> = 0.20). The dynamics appear consistent with expectations for the kinematically constrained reaction which supports the reaction type, heavy + light-heavy → heavy-light + heavy (H + LH′ → HL + H′). The dynamics of oxygen atom collision with HSiCl3 are discussed in comparison to those with SiH4. KCI Citation Count: 1