An investigation of the triplet state dynamics of zinc chlorophyll b by microwave-induced changes in the intensity of fluorescence and singlet-singlet absorption

Abstract

Optical detection of magnetic resonance experiments on the triplet state of zinc-substitution chlorophyll b has provided the zero-field splitting and depopulation rate constants for the individual triplet spin sublevels. The zero field triplet state EPR transitions could be observed at 890 MHz and 1085 MHz as either microwave-induced changes in the fluorescence intensity or in the intensity of S 0 → S n absorption. The dynamics experiments show that intersystem crossing from the Zn chlorophyll b triplet state into the ground state occurs primarily through the out-of-plane (lowest energy) spin sublevel.