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Author Rätsep, Margus ♦ Pajusalu, Mihkel ♦ Linnanto, Juha Matti ♦ Freiberg, Arvi
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CHLOROPHYLL ♦ COMPLEXES ♦ ELECTRON-PHONON COUPLING ♦ FLUORESCENCE SPECTROSCOPY ♦ HARVESTING ♦ MIXING ♦ MOLECULES ♦ PHONONS
Abstract We have observed that an assembly of the bacteriochloropyll a molecules into B850 and B875 groups of cyclic bacterial light-harvesting complexes LH2 and LH1, respectively, results an almost total loss of the intra-molecular vibronic structure in the fluorescence spectrum, and simultaneously, an essential enhancement of its phonon sideband due to electron-phonon coupling. While the suppression of the vibronic coupling in delocalized (excitonic) molecular systems is predictable, as also confirmed by our model calculations, a boost of the electron-phonon coupling is rather unexpected. The latter phenomenon is explained by exciton self-trapping, promoted by mixing the molecular exciton states with charge transfer states between the adjacent chromophores in the tightly packed B850 and B875 arrangements. Similar, although less dramatic trends were noted for the light-harvesting complexes containing chlorophyll pigments.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2014-10-21
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 141
Issue Number 15


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