LASER SPECTROSCOPY OF MODEL PHOTOSYNTHETIC SYSTEMS

Abstract— The goal of the present work was to create and investigate a model system, using a dye imbedded into polymer structure, and to examine characteristics which would provide low heat dissipation and excitation diffusion characteristics approaching those seen in the "antenna" of the photosynthetic apparatus. Zinc tetraphenoxyphtalocyanine served as a dye, and different types of polyvinyl pyridine polymers and polystyrene were used as polymer matricies. Measurements of the absorption, fluorescence and Raman spectra of the polymeric films with dye molecules show that along with Van der Waals interactions of the dye molecules with the side aromatic groups of the polymer there is a coordination interaction between the metal atoms of Zinc phtalocyanine and the nitrogen atoms of the pyridine group of the polymer. A model system shows low heat losses of excitation energy, when the dye concentration does not exceed 10^-2 M (mean distances between molecules of about 34 Å). Electronic excitation diffusion characteristics appeared to be close to those of the light harvesting antenna of the photosynthetic apparatus, indicating high efficiency of the energy migration in it.