Abstract
Singlet oxygen, lO2 (lΔg), which is the lowest electronically excited state of the oxygen molecule, is quenched by various compounds. In this article, the pressure effects on the physical quenching of lO2 (lΔg) by solvent molecules and amines, and also on the chemical reactions of lO2 (lΔg) with furans and tetramethylethylene (TME) (ene reaction) in liquid solution are reviewed. For these systems, the quenching mechanism is described.