Quantum Efficiency of Cytochrome Oxidation in a Photosynthetic Bacterium.

Illumination of Chromatium with light absorbed by bacteriochlorophyll causes the oxidation of intracellular cytochrome. The quantum efficiency of this reaction approaches one electron per photon at 589 millimicrons and at wavelengths between 862 and 908 millimicrons. The efficiency of converting excitation energy to chemical energy is estimated to be about 30 percent.