QUENCHING OF CHLOROPHYLL FLUORESCENCE BY NITROBENZENE

Autor:	C.J. Tredwell, L. Harris, G. S. Beddard, Sheena Carlin, George Porter
Rok vydání:	1978
Předmět:	Quenching (fluorescence) Chemistry Picosecond Analytical chemistry Fluorescence correlation spectroscopy General Medicine Physical and Theoretical Chemistry Nanosecond Biochemistry Fluorescence Chlorophyll fluorescence Photon counting Equilibrium constant
Zdroj:	Photochemistry and Photobiology. 27:433-438
ISSN:	1751-1097 0031-8655
DOI:	10.1111/j.1751-1097.1978.tb07625.x
Popis:	—Nitrobenzene quenching of chlorophyll fluorescence in ethanol has been investigated. Steady state relative quantum yields have been measured and fluorescence decay rates were determined using both nanosecond photon counting and picosecond pulses from a mode-locked Nd3+ glass laser. The fluorescence decay is described by 1(t)=I0 exp (-t/τ−At1/2) the form predicted for decay governed by the kinetics of the continuum model of diffusion controlled reactions. From the parameters of the fluorescence decay, the encounter distance is 5–7 A° the mutual diffusion coefficient is 0.62 × 10--5 cm2s-1± 12%. Some of the fluorescence quenching is also attributed to static quenching by a nitrobenzene-chlorophyll, ground-state complex. The equilibrium constant for formation of this ground-state complex was determined to be 4.1 M-1. The combined dynamic and static quenching model allows calculation of quantum yields of fluorescence in good agreement with the experimentally determined quantum yields.
Databáze:	OpenAIRE
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