ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
A photodissociation study of SO2 ⋅ O+2 is presented. The experiments were carried out on mass selected ion beams that were crossed with a polarized laser beam and then photoproducts were mass and energy analyzed. The SO2 ⋅ O+2 ions were formed by three body association reactions in a pressure and temperature dependent ion source. Studies were carried out at wavelengths of 582, 514, 488, 458, and 357±7 nm using an argon ion laser/dye laser system. Both O+2/SO2 and SO+2/O2 photoproducts were observed and the branching ratio measured as a function of λ. In addition, product kinetic energy distributions and angular distributions (asymmetry parameters) were measured and statistical phase space theory calculations were carried out. The results indicate the O+2/SO2 products are formed from photon absorption to a bound excited state at all wavelengths followed by internal conversion to the ground state and statistical vibrational predissociation. The SO+2/O2 products are formed by two mechanisms. At long wavelengths (582 nm) the products are formed exclusively by photon absorption to a bound state followed by internal conversion and statistical predissociation from the ground state. At short wavelengths (357 nm) direct dissociation from a repulsive upper state dominates. Both mechanisms are involved at intermediate wavelengths. Arguments are made that both the bound and repulsive upper states correlate to SO+2(X˜ 1A1)/O2(b 1∑+g) products and that the bound upper state corresponds to the low energy band in the photodissociation cross section measurements of Hodges and Vanderhoff and the repulsive state to the high energy band.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.451987
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