Intermediates in the chemiluminescent reaction of singlet oxygen with ethylene. Ab initio studies

The excited state of molecule, ¹O₂, is singlet dioxygen thought to play an important role in such biologically important phenomena as "photodynamic action" (photosensitized oxidation), photocarcinogenicity, photochemical smog formation, and bioluminescent processes. However, despite numerous experimental studies of the chemistry of ¹O₂, there is yet a great deal of uncertainty concerning the mechanism involved in the reactions of ¹O₂ and in the chemiluminescence that often results. In this paper we will use the results of ab initio studies (large basis including polarization functions; generalized valence bond with extensive configuration interaction) to examine the processes 1, 2, and 3.