[Study of different types of chlorophyll a aggregates in solutions and films by absorption and luminescence derivative spectroscopy]

Abstract

The second derivative of absorption, fluorescence and fluorescence excitation spectra of chlorophyll a in concentrated solutions and films was investigated. More than 14 forms of pigment aggregates, which can be divided into two types--with narrow 8-10nm) and wide (25-40nm) low temperature (-196 degrees C) spectra bands, were found. For the most part of the aggregated forms, the position and half width of the bands, as well as the Stokes shift and relative quantum yield were determined. The comparison of the spectral characteristics points to the indentity of the aggregates and corresponding native forms of Chl. a. It is shown that the universal relationship between absorption and fluorescence bands in applicable to the aggregates of the two types and the energy of resonance interaction between monomers in the aggregates is evaluated.