CAROTENOIDS AS ACCESSORY LIGHT-HARVESTING PIGMENTS

One of the main functions of carotenoids in photosynthesis is to act a s accessory light-harvesting molecules. This paper reviews the current status of research on the mechanism of this singlet-singlet energy tr ansfer process. Two excited singlet states S1 and S2 are described. Ba sed on fluorescence measurements the energy levels and lifetimes of th ese two states have been determined for a range of carotenoids. The ro le of these two states in this energy transfer process is discussed.