Conversion of SO_2 to SO_3 by In Situ Photolysis of SO_2 and O_3 Mixtures Isolated in Argon Matrixes: Isotopic Effects

摘要

The mechanism of photooxidation of sulfur dioxide in the presence of ozone and under irradiation at 266 nm has been investigated at low temperature in an argon matrix. Formation of stable SO_3 occurs from the reaction between SO_2 and O(~1D) and also by oxygen atom transfer within the SO_2 : O_3 complex. Use of isotopic SO_2 species led to unusual observations suggesting that photooxidation of SO_2 proceeds via an intermediate species, namely, OSOO; this trioxide sulfur isomer transforms into SO_3 by tunneling. In the gas phase, the quenching of the O(~1D) atom by SO_2 could occur through this intermediate.