PRODUCT STATE-RESOLVED STEREODYNAMICS OF THE REACTION O(D-1)-]OH+CH3(CH4)

Polarized, Doppler-resolved laser induced fluorescence spectroscopy ha s been employed to study the product state-resolved stereodynamics of the velocity aligned, hot atom reaction O(D-1) + CH4 --> OH((2) Pi(3/2 ),v=0,N=5) + CH3 at a mean collision energy of 39 kJ mol(-1). A forwar d simulation technique is used to extract product Lambda-doublet level specific differential cross sections and center-of-mass (CM) rotation al alignments from experimentally determined Doppler-resolved profiles . The results and analysis reveal (i) near conservation of kinetic ene rgy in the channel leading to vibrationless OH products and hence high internal excitation in the CH3 coproducts; (ii) indistinguishable dif ferential (k, k') cross sections for the two A-doublet components, bot h of which display pronounced forward and backward peaks, slightly wei ghted toward the backward hemisphere, and establish the intermediacy o f a long-lived collision complex, and (iii) contrasting CM rotational alignments for the two Lambda-doublet components, with a near isotropi c angular distribution of j' for OH Pi(A '') but a preferential j' per pendicular to k' polarization for the A' level. The results are compar ed with previous investigations of the OH(j = 4,N = 8) channel of the O(D-1) + CH4 reaction and similar studies by Hail et al. [J. Chem. Phy s. 1994, 101, 2033] of the H + O-2 --> OH + O reaction. It is suggeste d that the form of the measured differential cross sections in part re flects angular momentum conservation constraints imposed by low rotati onal excitation in both the observed OH fragment and its CH3 partner. The k, k', j' distributions, on the other hand, provide more detailed insight into the nuclear motions in the transition-state region and ev idence for electronic nonadiabaticity in the exit channel.