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 04:00:00 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]

---

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

Related Subjects

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