Measuring Electronic Coupling in the Reaction Center of Purple Photosynthetic Bacteria by Two-Color, Three-Pulse Photon Echo Peak Shift Spectroscopy
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- 作者：Dilworth Y. Parkinson ; Hohjai Lee ; Graham R. Fleming
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：June 28, 2007
- 年：2007
- 卷：111
- 期：25
- 页码：7449 - 7456
- 全文大小：113K
- 年卷期：v.111,no.25(June 28, 2007)
- ISSN：1520-5207
文摘
One- and two-color, three-pulse photon echo peak shift spectroscopy (1C and 2C3PEPS) was used to estimatethe electronic coupling between the accessory bacteriochlorophyll (B) and the bacteriopheophytin (H) in thereaction center of the purple photosynthetic bacterium Rhodobacter sphaeroides as ~170 ± 30 cm-1. This isthe first direct experimental determination of this parameter; it is within the range of values found in previouslypublished calculations. The 1C3PEPS signal of the Qy band of the bacteriochlorophyll B shows that it isweakly coupled to nuclear motions of the bath, whereas the 1C3PEPS signal of the Qy band of thebacteriopheophytin, H, shows that it is more strongly coupled to the bath, but has minimal inhomogeneousbroadening. Our simulations capture the major features of the data with the theoretical framework developedin our group to separately calculate the response functions and population dynamics.