Determination of O 2 (a¹Δ g ) and O 2 (b¹Σ + g ) yields in the reaction O + ClO → Cl + O 2 : Implications for photochemistry in the atmosphere of Venus

A discharge flow apparatus with chemiluminescence detector has been used to study the reaction O + ClO → Cl + O 2 * , where O 2 * = O 2 (a¹Δ g ) or O 2 (b¹Σ + g). The measured quantum yields for producing O 2 (a¹Δ g ) and O 2 (b¹Σ + g) in the above reaction are less than 2.5 × 10 −2 and equal to (4.4 ± 1.1) × 10 −4 , respectively. The observed O 2 (a¹Δ g ) airglow of Venus cannot be explained in the context of standard photochemistry using our experimental results and those reported in recent literature. The possibility of an alternative source of O atoms derived from SO 2 photolysis in the mesosphere of Venus is suggested.