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EFFICIENCY OF THE PHOTOPROCESSES LEADING TO SINGLET OXYGEN ( 1δ g ) GENERATION BY α‐TERTHIENYL: OPTICAL ABSORPTION, OPTOACOUSTIC CALORIMETRY AND INFRARED LUMINESCENCE STUDIES*
Author(s) -
Scaiano J. C.,
Redmond R. W.,
Mehta B.,
Arnason J. T.
Publication year - 1990
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.1751-1097.1990.tb08663.x
Subject(s) - intersystem crossing , chemistry , phosphorescence , photochemistry , singlet oxygen , absorption (acoustics) , calorimetry , luminescence , singlet state , infrared , polar , photodissociation , oxygen , fluorescence , excited state , atomic physics , materials science , optoelectronics , optics , organic chemistry , thermodynamics , physics , astronomy
— …The triplet energy of α‐terthienyl has been determined by heavy atom‐induced optical absorption; the value of 39.7 ±1.5 kcal/mol is consistent with earlier energy transfer work. Combining this result with calorimetric data from optoacoustic calorimetry indicates that intersystem crossing occurs with at least 90% efficiency in polar and non‐polar solvents. The quantum yields for singlet oxygen formation via energy transfer from triplet α‐terthienyl have been obtained from time‐resolved measurements of its IR phosphorescence; these yields are in the 0.6‐0.8 range in non‐polar and polar (hydroxylic and non‐hydroxylic) solvents.