The nascent rotational and λ-doublet state distributions of OH produced in the reaction H+O2→OH(N,v,f )+O were probed by fast atom–laser induced fluorescence experiments at average collision energies E=100, 183, 200, 220, and 243 kJ/mol. With increasing E, the rotational product distributions become increasingly nonstatistical with a narrow peak at high rotational states, in good agreement with quasiclassical trajectory calculations on an ab initio potential energy surface. The calculations show the narrow product rotational peak to be due to an increasing specifity of the initial H–O2 configurations leading to reactions. At high E the impact parameters and initial polar angles are confined to a rather small range allowing reaction only for an optimal approach. The OH λ-doublet distributions show preference for the Π(A′) component probed by R lines at all collision energies investigated. This suggests a planar reaction path and little importance of out of plane rotation of the HO2 complex at the high collision energies of the experiment. The experimental λ-doublet distributions are quantitatively compared with the degree of in-plane scattering obtained from the trajectory calculations.

Crossed molecular beams study of the reaction D+H2→DH+H at collision energies of 0.53 and 1.01 eV J. Chem. Phys. 93, 5719 (1990); 10.1063/1.459566 Experimental study of the dynamics of D+H2 reactive and inelastic collisions below 1.0 eV relative energy J. Chem. Phys. 90, 1600 (1989); 10.1063/1.456052 Dynamics of the H+D2→HD+D reaction: Dependence of the product quantum state distributions on collision energy from 0.98 to 1.3 eV J. Chem. Phys. 82, 1323 (1985); 10.1063/1.448455 Experimental study of the dynamics of the H+D2→HD+D reaction at collision energies of 0.55 and 1.30 eV The nascent rotational and fine structure state distributions of OH produced in the reaction H + 02---+0H (N,v,f) + 0 were probed by fast atom-laser induced fluorescence experiments.Translationally hot H atoms were formed by photolysis ofHJ and HBr at 248 and 193 nm leading to H + O 2 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 A-doublet distributions show preference for the 1T+ component which increases with increasing E suggesting less importance of out of plane rotation of the H0 2 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.

5543combination to measure the nascent rotational and vibrational distributions of excited C02 molecules created by a variety of chemically interesting processes such as photodiss~ciation,~~ electronic quenching,16 inelastic scattering," and bimolecular and (15) ONeill, J. A.; Kreutz, T. G.; Flynn, G. W., accepted for publication in The photoemission spectrum of H2S excited at 193 nm, near the maximum of its first absorption band, contains long progressions of stretch and stretch-bend combination bands but no progression solely of the bend vibration in the region 193-320 nm. The results are interpreted in terms of the dissociation dynamics at very short and at intermediate times.

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