EFFECTS OF MOLECULAR-ORGANIZATION ON PHOTOPHYSICAL BEHAVIOR - LIFETIME AND STEADY-STATE FLUORESCENCE OF CHLOROPHYLL-A SINGLETS IN MONOLAYERS OF DIOLEOYLPHOSPHATIDYLCHOLINE AT THE NITROGEN WATER INTERFACE
EFFECTS OF MOLECULAR-ORGANIZATION ON PHOTOPHYSICAL BEHAVIOR - LIFETIME AND STEADY-STATE FLUORESCENCE OF CHLOROPHYLL-A SINGLETS IN MONOLAYERS OF DIOLEOYLPHOSPHATIDYLCHOLINE AT THE NITROGEN WATER INTERFACE
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DOI：
10.1021/j100260a005
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发表时间：
1985-01-01
影响因子：
--
通讯作者：
PATTERSON, LK
中科院分区：
文献类型：
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作者：
AGRAWAL, ML;CHAUVET, JP;PATTERSON, LK
The fluorescence lifetimes of the chlorophyll a singlet have been measured in spread monolayers of dioleoylphosphatidylchollne at the nitrogen-water interface. Determinations were made as functions of both chlorophyll concentration and compression. A single exponential decay with a lifetime of 5.5±0.3 ns was observed at 0.0084 mole fraction chlorophyll; this falls to 1.0±0.1 ns at 0.0800 mole fraction. Such findings indicate a limiting quantum yield approaching that found in isotropic polar media as well as vesicles; it is about 90% of that found in nonpolar media. Fluorescence and excitation spectra have also been obtained. An unstructured fluorescence band is observed with a maximum at 678.5±0.5 nm, indicating that the monomer is the predominant fluorescent formof chlorophyll a. Fluorescence intensity data in the same concentration range are presented for comparison. Plots of both intensity and lifetime, normalized to values obtained at infinite dilution, as functions of molecules/cm1 2, coincide quite closely. The agreement between these two types of data—while indicating that statistical chlorophyll a pairs are involved in the quenching mechanism—suggests that both fluorescence and energy transfer from such pairs compete with the process of quenching.
