title: [Quantum differences of ortho/para H2O2 spin-isomers as a factor of the femtosecond charge separation kinetics modulation in reaction centers of purple bacteria].
abstract: We have proposed the mechanism of coherent modulations of the P* state in the transient absorption spectra of the reaction center isolated from purple bacteria. Two water molecules, located between special pair, Ba, Bb chlorophylls and histidine L173 and M202, are supposed to be ortho-H2O and para-H2O isomers with different magnetic properties. The distinctive modulation frequencies were labeling as rotational resonances of ortho-H2O. According to our assumption, the interaction of rotational modes of water isomers with the charge-transfer states is a reason of coherent modulations of kinetics. We have modified a Hamiltonian system in order to take into account the rotational modes of ortho-H2O. Evolution of the density matrix was calculated in Liouville space. The Redfield relaxation theory for molecular aggregates was used to model kinetics up to 3 ps.
authors.forename: R Iu
authors.initials: RIu
authors.lastname: Pishchal'nikov
authors.forename: S M
authors.initials: SM
authors.lastname: Pershin
authors.forename: A F
authors.initials: AF
authors.lastname: Bunkin
mesh_terms: D001429:Bacteriochlorophylls / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D006639:Histidine / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D020560:Proteobacteria / Q000737:chemistry; D011789:Quantum Theory; D013113:Spin Labels; D014867:Water / Q000737:chemistry*
chemical_list: D001429:Bacteriochlorophylls; D045322:Photosynthetic Reaction Center Complex Proteins; D013113:Spin Labels; C107900:bacteriochlorophyll b; D014867:Water; D006639:Histidine; D006861:Hydrogen Peroxide