The Fenna−Matthews−Olson (FMO) photosynthetic complex found in green sulfur bacteria has been one of the favorite “model” systems for biological energy transfer over the last decades. However, even after 40 years of studies, quantitative knowledge about its energy-transfer properties is limited.
We applied two-dimensional electronic spectroscopy with full polari-zation control to provide an accurate description of the electronic structure and population dynamics in the complex. The sensitivity of the technique has further allowed us to spectroscopically identify the eighth bacterio-chlorophyll molecules recently discovered in the crystal structure. The time evolution of the spectral structure, covering time scales from tens of femtoseconds up to a nanosecond, reflected the energy flow in FMO and enabled us to extract an unambiguous energy-transfer scheme.
E. Thyrhaug, K. Židek, J. Dostál, D. Bína, D. Zigmantas, Exciton Structure and Energy Transfer in the Fenna–Matthews–Olson Complex. J. Phys. Chem. Lett. 7(9), 1653-1660 (2016).