THE STUDY OF DELOCALIZED STATES IN THE AN TENNA OF PURPLE BACTERIA BYNONLINEAR SPECTROSCOPY

The magnitude of photoinduced absorbance changes in the longwavelength absorption band of antenna containing preparations from purple photos ynthetic bacteria Rhodospirillum rubrum, Rhodopseudomonas viridis and Chromatium minutissimum was studied. The bleaching value at peak of th e <<minor>> spectral form of the antenna was 4-16 times that of the co rresponding value at peak of bacteriochlorophyll of the special pair o f reaction center. A theory of this effect at the base of excitation d elocalization over circular aggregate of antenna bacteriochlorophylls proposed earlier is presented. It is concluded that anomalously high v alues of photoinduced absorbance changes In the antenna of photosynthe tic purple bacteria are the direct evidence of long-lived exciton delo calization over all core antenna bacteriochlorophylls.