Atmospheric chemistry of CF3O2: a theoretical study on mechanisms and pathways of the CF3O2 + IO reaction

Abstract

The mechanisms and reaction pathways for the CF₃O₂ + IO reaction have been investigated by quantum chemistry methods. It has been found that the title reaction takes place on both the singlet and triplet potential energy surfaces (PES). On the singlet PES, the most important products include CF₃OOOI, CF₃OOIO, CF₃OIO₂, and CF₂O + FIO₂, while other products such as CF₂O + FOIO, CF₂O + FOOI, CF₃OOI + O(³P), CF₃OI + O₂ (¹Δ and ³Σ), and CF₃O + OIO are negligible due to high barriers or unstable formations. On the triplet PES, CF₃O + OIO is the dominant product with a lower barrier. As for FIO₂ and it isomers, the most stable one is FIO₂. TDDFT (Time Dependent Density Functional Theory) calculation indicates that CF₃OOOI, CF₃OOIO and CF₃OIO₂ undergo photolysis easily under sunlight. Moreover, a minor contribution relative to hydrogen is found in the CX₃O₂ + IO (X = H and F) reactions.