Some Photochemical Reactions of O3 in the Gas Phase

Abstract

When a gaseous mixture containing O₃ and CO₂ of different isotopic composition is illuminated by uv light, the oxygen that is formed has undergone some exchange with CO₂. The extent of this exchange has been studied as a function of initial O₃ and CO₂ pressure, and the influence of foreign gases on it was also studied. It is concluded that O¹D is the intermediate which undergoes rapid exchange with CO₂, and further that the reaction $${\mathrm{O}}^1\mathrm{D}+{\mathrm{CO}}_2\rightleftharpoons \mathrm{CO}+{\mathrm{O}}_2$$ does not provide the dominant mechanism for this exchange. The results suggest that at low total pressures exchange takes place by $${\mathrm{O}}^{*}+{\mathrm{CO}}_2\rightleftharpoons \mathrm{O}+{\mathrm{CO}}_2^{*}$$ and that at high total pressures, CO₃ is formed as an intermediate.