Coherence Dynamics in Photosynthesis: Protein Protection of Excitonic Coherence

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Science  08 Jun 2007:
Vol. 316, Issue 5830, pp. 1462-1465
DOI: 10.1126/science.1142188
  • Fig. 1.

    The 2CECPE experiment. (A) The 77 K absorption spectrum (black) of the P-oxidized RC from the photosynthetic purple bacterium R. sphaeroides and the spectral profiles of the ∼40-fs laser pulses (blue, 750 nm; red, 800 nm) used in the experiment. (B) The pulse sequence for the 2CECPE experiment. We detect the integrated intensity in the phase-matched direction ks = –k1 + k2 + k3. a.u., arbitrary units.

  • Fig. 2.

    Two-dimensional maps of experimental (A and B) and simulated (C and D) integrated echo signals as a function of the two delay times, t1 and t2, from the RC. The black lines follow the maximum of the echo signal at a given t2. The data at t2 < 75 fs are not shown because the conventional two-color three-pulse photon echo signal (750-750-800 nm) overwhelms the 2CECPE signal in this region, due to the pulse overlap effect.

  • Fig. 3.

    Integrated echo signals as a function of t2 at t1 = 30 fs. Because the system evolves as a coherence between the H and B excitons during the t2 period, this plot represents the dephasing dynamics of the |B 〉 〈H| coherence. Measurements at 77 K (A) and 180 K (B) are shown in solid circles, and the theoretical curves are shown in red (c = 0.9) or blue (c = 0.6) lines. a.u., arbitrary units.

Additional Files

  • Coherence Dynamics in Photosynthesis: Protein Protection of Excitonic Coherence/STRONG>
    Hohjai Lee, Yuan-Chung Cheng, Graham R. Fleming

    Supporting Online Material

    This supplement contains:
    Materials and Methods
    Figs. S1 and S2

    This file is in Adobe Acrobat PDF format.

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