Experimental study of H+O2 reaction dynamics at collision energies of 2.6, 1.9, and 1.0 eV

Abstract

The nascent rotational and fine structure state distributions of OH produced in the reaction H+O2→OH (N,v, f)+O were probed by fast atom-laser induced fluorescence experiments. Translationally hot H atoms were formed by photolysis of HJ and HBr at 248 and 193 nm leading to H+O2 c.m. collision energies E of 2.6, 1.9, and 0.9 eV. The rotational state distributions are compared with trajectory calculations using the ab initio potential energy surface of Melius and Blint. The OH λ-doublet distributions show preference for the π+ component which increases with increasing E suggesting less importance of out of plane rotation of the HO2 complex at high E. The alignment of OH relative to the flight direction of the H atoms is measured by polarizing analysis and photolysis laser beams. The large polarization effects directly demonstrate that the OH angular momentum vectors are preferentially parallel to the electrical vector of the dissociation laser and perpendicular to the flight direction of the H atoms.