THE INFLUENCE OF RIGID MATRICES ON THE PROCESSES OF DEACTIVATION OF EXCITED BACTERIOCHLOROPHYLL-C

Bacteriochlorophyll c is a main pigment of green photosynthetic bacter ia which is occurring in these organisms in various states of aggregat ion. Spectral properties such as absorption, fluorescence, delayed lum inescence and photoacoustic spectra of bacteriochlorophyll c in two ri gid matrices: silica glass and polymethylmethacrylate were established . The different photoproducts and aggregates of bacteriochlorophyll c exhibit various yields of thermal deactivation. Absorptions of some ph otoproducts are similar therefore the photoacoustic spectra are very u seful in the investigations of the photochemical reactions. The pigmen ts are more photochemically stable in silica glass than in polymer, wh ich is due to the efficient quenching of triplet states in the silica glass. (C) 1998 Elsevier Science S.A. All rights reserved.