title: Role of electronic-vibrational mixing in enhancing vibrational coherences in the ground electronic states of photosynthetic bacterial reaction center.
abstract: We describe polarization controlled two-color coherence photon echo studies of the reaction center complex from a purple bacterium Rhodobacter sphaeroides. Long-lived oscillatory signals that persist up to 2 ps are observed in neutral, oxidized, and mutant (lacking the special pair) reaction centers, for both (0°,0°,0°,0°) and (45°,-45°,90°,0°) polarization sequences. We show that the long-lived signals arise via vibronic coupling of the bacteriopheophytin (H) and accessory bacteriochlorophyll (B) pigments that leads to vibrational wavepackets in the B ground electronic state. Fourier analysis of the data suggests that the 685 cm(-1) mode of B may play a key role in the H to B energy transfer.
authors.affiliation: Department of Chemistry, University of California-Berkeley , and Physical Bioscience Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Ian Seungwan
authors.initials: IS
authors.lastname: Ryu
authors.forename: Hui
authors.initials: H
authors.lastname: Dong
authors.forename: Graham R
authors.initials: GR
authors.lastname: Fleming
mesh_terms: D001429:Bacteriochlorophylls / Q000737:chemistry; D004583:Electrons; D004735:Energy Transfer; D010674:Pheophytins / Q000737:chemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000378:metabolism; D014732:Vibration
chemical_list: D001429:Bacteriochlorophylls; D010674:Pheophytins; D045322:Photosynthetic Reaction Center Complex Proteins; C006678:bacteriopheophytin