Effect of nonexcitonic interactions among the paired molecules on the Q sub y transition of bacteriochlorophyll dimers. Applications to the primary electron donors P-860 and P-960 in bacterial reaction centers

Journal Article · Wed Jan 16 00:00:00 EST 1991 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00002a047· OSTI ID:5212412

Rosenbach-Belkin, V; Fisher, J R.E.; Scherz, A ^[1]

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1. Weizmann Inst. of Science, Rehovot (Israel)

X-ray diffraction of reaction centers (RCs) from two strains of purple bacteria, Rhodobacter sphaeroides and Rhodopseudomonas viridis, revealed that their primary electron donors, P-860 and P-960, are tight dimers of bacteriochlorophyll (Bchl) a and b, respectively. The geometry of the paired molecules is such that their transition monopoles strongly interact, resulting in a bathochromic shift of the Q{sub y} bands. Recent calculations based upon interactions among point-charge monopoles (PCM) showed that exciton coupling among the localized Q{sub y} transitions of the paired molecules can account for part of the shift. The origin of the remaining nonexcitonic shift is controversial. In this communication the authors show that there is a ratio of 1.2-1.5 between the nonexcitonic shift and the exciton splitting of the Q{sub y} transition in several Bchl dimers in vitro.

• OSTI ID: 5212412
• Journal Information: Journal of the American Chemical Society; (United States), Vol. 113:2; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PHOTOSYNTHETIC REACTION CENTERS
ABSORPTION SPECTRA
EXPERIMENTAL DATA
MEASURING METHODS
PHOTOCHEMISTRY
PHOTOSYNTHESIS
PHOTOSYNTHETIC BACTERIA
CHEMICAL REACTIONS
CHEMISTRY
DATA
INFORMATION
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
SPECTRA
SYNTHESIS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400500 - Photochemistry