title: Exciton delocalization probed by excitation annihilation in the light-harvesting antenna LH2.
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.
authors.affiliation: Institute of Physics, Vilnius 2600, Lithuania.
authors.forename: G
authors.initials: G
authors.lastname: Trinkunas
authors.forename: J L
authors.initials: JL
authors.lastname: Herek
authors.forename: T
authors.initials: T
authors.lastname: Polívka
authors.forename: V
authors.initials: V
authors.lastname: Sundström
authors.forename: T
authors.initials: T
authors.lastname: Pullerits
mesh_terms: D016880:Anisotropy; D001426:Bacterial Proteins; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes; D010788:Photosynthesis / Q000502:physiology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D012242:Rhodobacter sphaeroides / Q000737:chemistry / Q000502:physiology*; D013057:Spectrum Analysis
chemical_list: D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C023693:protein complex B800-850, Rhodobacter