Excited-state structure and energy-transfer dynamics of the bacteriochlorophyll a antenna complex from Prosthecochloris aestuarii

Journal Article · Wed Jan 09 23:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100154a083· OSTI ID:5796318

Johnson, S G; Small, G J ^[1]

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1. Ames Lab., IA (USA)

Persistent nonphotochemical hole-burning results at 4.2 K are reported for an antenna complex of the photosynthetic bacterium Prosthecochloris aestuarii which consists of a trimer of subunits with each subunit containing seven bacteriochlorophyll a (BChl a) molecules. The data for the Q{sub y} (S{sub 1}) region are consistent with an excitonically coupled system and indicate the existence of more than seven exciton levels, with two contributing to the lowest energy absorption band at 825 nm. State assignments are discussed in terms of various models, including one that invokes interaction between BChl a belonging to different subunits of the same trimer. Exciton level decay times are reported and discussed in terms of exciton-phonon scattering involving phonon emission. These times are compared to and discussed in terms of the ultrafast ({approx lt} 100 fs) decay times for the accessory pigment Q{sub y} states of the bacterial RC. The hole spectra also allows for the determination of the linear exciton-phonon coupling strength (optical reorganization energy) and the contribution of complex heterogeneity to the line widths of the absorption profiles.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5796318
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:1; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
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59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTRA
CHEMICAL REACTIONS
DATA
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
EXPERIMENTAL DATA
INFORMATION
MEASURING METHODS
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
SPECTRA
SYNTHESIS
ULTRALOW TEMPERATURE