Oxygen quenching of aromatic triplet states in solution. Part 2

Abstract

Recent measurements of the quenching of aromatic triplet states by oxygen are discussed. The dependence of the quenching rate constant on triplet energy is analysed in terms of a nonradiative transition within the collision complex between a ground state oxygen and a triplet state aromatic molecule. The Franck-Condon factor and electronic matrix element for this transition are considered. It is shown that the data are consistent with symmetry restrictions in the formation of ¹∑⁺_g oxygen. Quantum yields of ¹∑⁺_g formation are calculated from the observed quenching rate constants and compared with experiment.