title: Energy transfer pathways in light-harvesting complexes of purple bacteria as revealed by global kinetic analysis of two-dimensional transient spectra.
abstract: Excited state dynamics in LH2 complexes of two purple bacterial species were studied by broad-band two-dimensional electronic spectroscopy. The optical response was measured in the 500-600 nm spectral region on the 0-400 fs time scale. Global target analysis of two-dimensional (2D) transient spectra revealed the main energy transfer pathways between carotenoid S2, 1Bu(-) and S1 states and bacteriochlorophyll Qx state. Global analysis ascertained the evolutionary and vibration-associated spectra, which also indicated the presence of a higher-lying vibrational level in the carotenoid S1 state. The estimation of the spectral overlap between the 1Bu(-) state and the Qx state indicated a significant contribution of the 1Bu(-) state to the overall S2-to-Qx excitation energy transfer.
authors.affiliation: Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
authors.forename: Evgeny E
authors.initials: EE
authors.lastname: Ostroumov
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Mulvaney
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Anna
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cogdell
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Scholes
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001429:Bacteriochlorophylls / Q000737:chemistry; D002338:Carotenoids / Q000737:chemistry; D004735:Energy Transfer; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D056951:Photoelectron Spectroscopy; D020560:Proteobacteria / Q000378:metabolism*; D016992:Rhodobacter / Q000378:metabolism; D012241:Rhodopseudomonas / Q000378:metabolism; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes; D002338:Carotenoids