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Proceedings Paper

Ultrafast dynamics of excitation energy transfer and trapping in bacterial photosynthesis
Author(s): Villy Sundstrom; Rienk van Grondelle
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Paper Abstract

With infrared transient absorption spectroscopy we have studied how energy migrates through the light-harvesting antenna of photosynthetic purple bacteria, and how the energy is trapped by the reaction center. In Bchl a-containing purple bacteria the light-harvesting (LH) antenna is highly heterogeneous, consisting of several spectroscopically distinct pigments. Energy transfer among these pigments occurs on several different time-scales. The overall trapping time at room temperature is about 60 ps, while energy transfer from the high-energy to the low-energy pigments of the lightharvesting antenna only takes 10 ps (measured at 77 K). This implies that trapping is relatively slow, 35 ps at 77 K and probably not much faster at room temperature. Energy transfer among neighboring Bchl molecules within a pigment-protein complex occurs on the 1 ps to subpicosecond time scale. For the Bchl b-containing purple bacterium Rps.viridis the results show that the antenna is homogeneous, and trapping can approximately be described by a randomwalk model, provided that the light-harvesting antenna and reaction center are more tightly coupled than in the Bchl a containingpurple bacteria.

Paper Details

Date Published: 17 June 1993
PDF: 10 pages
Proc. SPIE 1921, Laser Spectroscopy of Biomolecules, (17 June 1993); doi: 10.1117/12.146155
Show Author Affiliations
Villy Sundstrom, Univ. of Umea (Sweden)
Rienk van Grondelle, Free Univ. (Netherlands)


Published in SPIE Proceedings Vol. 1921:
Laser Spectroscopy of Biomolecules

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