Electron-impact excitation of sulphur dioxide at energies > ca. 10 eV results in optical emission from the Ã 3? and B~ 3S states of the SO radical. The threshold energy for production of the SO(Ã 3?) was found to be 10.6 ± 0.5 eV, a value similar to the minimum thermochemical energy requirements. Optical emission excitation functions for the SO(Ã) state show that in the energy region 10-20 eV an important excitation channel involves the triplet manifold of sulphur dioxide, although there is still a significant contribution from singlet excitation, particularly at higher energies. The SO(Ã) state is quenched by molecular SO2 with near-unit collisional efficiency, with an estimated rate constant of 8.4 × 10-11 cm3 molecule-1 s-1. Detailed studies on production of SO(B~) could not be undertaken owing to considerable spectral interference from molecular sulphur dioxide emission.
|Number of pages||6|
|Journal||Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics|
|Publication status||Published - 1987|