Ultrafast energy-transfer pathway in a purple-bacterial photosynthetic core antenna, as revealed by femtosecond time-resolved spectroscopy

Reaping a good light harvest: Femtosecond spectroscopy uncovered a novel pathway of singlet-singlet excitation-energy transfer (EET) from bacteriochlorophyll (Bchl) in a purple bacterium to the carotenoid spirilloxanthin (Spx) upon the excitation of Bchl into the Qx band (see picture). This pathway was also clearly identified in steady-state fluorescence excitation spectra, but only in the presence of Spx. IC=internal conversion