Ultrafast exciton relaxation in the B850 antenna complex of Rhodobacter sphaeroides

Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):13774-9. doi: 10.1073/pnas.93.24.13774.

Abstract

Spectral changes were measured with femtosecond resolution following low-intensity, broad-band excitation of the peripheral antenna complex of the purple photosynthetic bacterium Rhodobacter sphaeroides. Absorption anisotropy decays also were measured. We identified a 35-fs relaxation of the absorption and emission spectra of the excited state, as well as a 20-fs anisotropy decay. We interpret these results as interlevel relaxation and dephasing, respectively, of extensively delocalized exciton states of the circular bacteriochlorophyll aggregate.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Chromatophores / physiology
  • Genes, Bacterial
  • Lasers
  • Light-Harvesting Protein Complexes
  • Photosynthetic Reaction Center Complex Proteins / biosynthesis
  • Photosynthetic Reaction Center Complex Proteins / chemistry*
  • Rhodobacter sphaeroides / genetics
  • Rhodobacter sphaeroides / metabolism*
  • Sequence Deletion
  • Spectrophotometry, Infrared
  • Thermodynamics
  • Time Factors

Substances

  • Light-Harvesting Protein Complexes
  • Photosynthetic Reaction Center Complex Proteins