[Photogeneration of singlet oxygen by psoralens]

Photosensitized luminescence of singlet (1 delta g) molecular oxygen with the maximum at 1272 nm has been found in solutions of psoralen, angelicin and 8-methoxypsoralen in CCl4. The luminescence excitation spectra, quantum yields of generation (gamma g) and rate constants of quenching (Kq) of 1 delta g by psoralens have been measured. The gamma g values 0,0055, 0,0026, 0,002 and Kq values 9 X 10(3), 11 X 10(3) and 12 X X 10(3) have been obtained for psoralen, angelicin and 8-methoxypsoralen, respectively. The role of 1 delta g in a photobiological action of psoralens is discussed.