We clearly demonstrate the occurrence of energy transfer between 18O2 (1Δg) and 16O2 in the ground state (3Σg-) with subsequent conversion of the latter species into its singlet excited state (1Δg) in aqueous solution. This was inferred from the results of incubation experiments involving DHPN18O2 as a chemical generator of 18O2 (1Δg) and the water-soluble disodium salt of anthracene (EAS) used as a chemical trap of singlet oxygen. The products of the reaction were accurately analyzed by HPLC-ESI-MS.
