Ultrafast exciton relaxation in the B850 antenna complex of Rhodobacter sphaeroides.
Spectral changes were measured with femtosecond resolution following low-intensity, broad-band excitation of the peripheral antenna complex of the purple photosynthetic bacterium Rhodobacter sphaeroides. Absorption anisotropy decays also were measured. We identified a 35-fs relaxation of the absorption and emission spectra of the excited state, as well as a 20-fs anisotropy decay. We interpret these results as interlevel relaxation and dephasing, respectively, of extensively delocalized exciton states of the circular bacteriochlorophyll aggregate.
Nagarajan
V
V
Department of Biochemistry, University of Washington, Seattle 98195, USA.
Alden
R G
RG
Williams
J C
JC
Parson
W W
WW
D020130:Bacterial Chromatophores / Q000502:physiology; D005798:Genes, Bacterial; D007834:Lasers; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000096:biosynthesis / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D013055:Spectrophotometry, Infrared; D013816:Thermodynamics; D013997:Time Factors
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins