Excitation transfer between components of molecular layers of cyanine compounds

Using the example of layers of symmetric polymethine dyes, we have studied the optical excitation energy transfer processes between nanocomponents of a molecular layer. The fluorescence yields and life-times of excited states of monomeric stereoisomers have been estimated, and the stereoisomerization yields have been determined. We show that the excitation transfer yield between the S1 states of monomeric stereoisomers (tens of percent) is considerably higher than the fluorescence yield (several percent) and depends on the structure of terminal groups of the molecule.