title: A photoinduced persistent structural transformation of the special pair of a bacterial reaction center.
abstract: Structural modification of photosynthetic reaction centers is an important approach for understanding their charge-separation processes. An unprecedented persistent structural transformation of the special pair (dimer) of bacteriochlorophyll molecules can be produced by light absorption alone. The nonphotochemical hole-burned spectra for the reaction center of Rhodopseudomonas viridis show that the phototransformation leads to a red shift of 150 wave numbers for the special pair's lowest energy absorption band, P960, and a comparable blue shift for a state at 850 nanometers, which can now be definitively assigned as being most closely associated with the upper dimer component. Additional insights on excited-state electronic structure include the identification of a new state.
authors.forename: N R
authors.initials: NR
authors.lastname: Reddy
authors.forename: S V
authors.initials: SV
authors.lastname: Kolaczkowski
authors.forename: G J
authors.initials: GJ
authors.lastname: Small