The Fluorescence Dynamics of Chlorophyll a and Sodium Magnesium Chlorophyllin

The concentration dependence of the fluorescence spectra and lifetimes of chlorophyll a and sodium magnesium chlorophyllin are compared to explore the influences of intramolecular relaxation and intermolecular interaction of chlorophylls on the fluorescence dynamics. With different concentrations of chlorophyll a and sodium magnesium chlorophyllin in the suspensions, three different fluorescence emission bands are observed. Intermolecular interactions increase as the concentrations increase, which lead to redshifts in both fluorescence and lifetime spectra. Additionally, the lifetime is increased by re-absorption in the sodium magnesium chlorophyllin suspensions. These observations increase the understanding of the light harvesting and energy relaxation mechanisms of chlorophyll molecules.