Exciton delocalization probed by excitation annihilation in the light-harvesting antenna LH2

Phys Rev Lett. 2001 Apr 30;86(18):4167-70. doi: 10.1103/PhysRevLett.86.4167.

Abstract

Singlet-singlet annihilation is used to study exciton delocalization in the light harvesting antenna complex LH2 (B800-B850) from the photosynthetic purple bacterium Rhodobacter sphaeroides. The characteristic femtosecond decay constants of the high intensity isotropic and the low intensity anisotropy kinetics of the B850 ring are related to the hopping time tau(h) and the coherence length N(coh) of the exciton. Our analysis yields N(coh) = 2.8+/-0.4 and tau(h) = 0.27+/-0.05 ps. This approach can be seen as an extension to the concept of the spectroscopic ruler.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anisotropy
  • Bacterial Proteins*
  • Kinetics
  • Light-Harvesting Protein Complexes*
  • Photosynthesis / physiology
  • Photosynthetic Reaction Center Complex Proteins / chemistry*
  • Photosystem II Protein Complex*
  • Rhodobacter sphaeroides / chemistry
  • Rhodobacter sphaeroides / physiology*
  • Spectrum Analysis

Substances

  • Bacterial Proteins
  • Light-Harvesting Protein Complexes
  • Photosynthetic Reaction Center Complex Proteins
  • Photosystem II Protein Complex
  • protein complex B800-850, Rhodobacter