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LASER PHOTOLYSIS STUDIES OF QUINONE REDUCTION BY CHLOROPHYLL a IN ALCOHOL SOLUTION
Author(s) -
Tollin Gordon,
Castelli Francesco,
Cheddar Glen,
Rizzuto Frank
Publication year - 1979
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.1751-1097.1979.tb09273.x
Subject(s) - quinone , semiquinone , chemistry , photochemistry , quenching (fluorescence) , triplet state , quantum yield , chlorophyll , reaction rate constant , solvent , photodissociation , chlorophyll a , fluorescence , kinetics , stereochemistry , organic chemistry , molecule , optics , biochemistry , physics , quantum mechanics
— Upon laser photolysis of chlorophyll‐quinone solutions in ethanol, transients due to the chlorophyll triplet state ( C t ), the chlorophyll cation radical (C + ) and the semiquinone radical (Q ‐ ) can be observed. The rise of Q ‐ parallels the decay of C t . demonstrating the precursor role of the triplet. The decay of C + is second order, consistent with reverse electron transfer, and has a rate constant which is independent of quinone potential, and an activation energy of 14kJ/mol due mainly to the temperature dependence of solvent viscosity. Triplet quenching and C + yield are found to decrease with decreasing quinone potential.