The dynamics of the light atom transfer reaction O(3PJ)+HBr→ OH(v′, j ′)+Br(2PJ ′)

Abstract

The dynamics of the title light-atom transfer reaction have been investigated using laser pump and probe techniques at a mean collision energy close to 0.3 eV. The experiments employed 308 nm photodissociation of NO2 to generate translationally excited O(3P) atoms, and were conducted at room temperature. OH quantum state populations were found to be in excellent accord with those determined by McKendrick et al. [Faraday Discuss. Chem. Soc., 1987, 84, 39]. OH Doppler resolved laser induced fluorescence was used to determine the angular distribution of the scattered OH products. For OH(2Π3/2, A′) born in (′ = 1, N′ = 5) the angular distribution was found to be broad, but peaked towards the forward direction, consistent with expectation based on kinematic considerations. More interestingly, a consistent fit to the experimental data could only be achieved by assuming that 10% of the OH(′ = 1, N′ = 5) products are partnered by spin–orbit excited state Br(2P1/2) atoms. The data suggest that at comparable energies above their respective energetic thresholds, the reaction cross-sections for production of OH(2Π3/2, A′, ′ = 1, N′ = 5) in conjunction with Br and Br* are similar.