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IS SINGLET OXYGEN FORMATION DOMINANT IN TRIPLET QUENCHING PROCESSES? MEASUREMENT OF THE QUANTUM YIELD OF SINGLET OXYGEN FORMATION BY THE TIME‐RESOLVED THERMAL LENS METHOD
Author(s) -
Terazima Masahide,
Tonooka Mizuho,
Azumi Tohru
Publication year - 1991
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1991.tb01985.x
Subject(s) - singlet oxygen , quenching (fluorescence) , photochemistry , triplet state , singlet state , quantum yield , chemistry , oxygen , benzene , limiting oxygen concentration , extrapolation , fluorescence , excited state , molecule , atomic physics , optics , physics , organic chemistry , mathematical analysis , mathematics
Abstract The quantum yields of singlet oxygen formation (Ø Δ ) by the quenching of triplet states of organic sensitizers are measured at various concentrations of the sensitizers by using the time‐resolved thermal lens method. Above a certain concentration, Ø Δ is independent of the sensitizer concentration. Below the threshold, Ø Δ gradually decreases as the concentration of the sensitizer decreases. The extrapolation of Ø Δ to zero concentration indicates that singlet oxygen formation is not necessarily dominant in the quenching process even for the 3 ππ* state in benzene.