Abstract

Electronic excitation transfer has been the subject of numerous experimental and theoretical studies. Recent experimental measurements of time-resolved fluorescence and pump-probe anisotropy have revealed sub-picosecond excitation transfer processes, seen as decays in the anisotropy. The experiments of Xie et al.[1] on Allophycocyanin (APC) and C-Phycocyanin (C-PC) isolated from photosynthetic antenna systems in cyanobacteria, measuring time-resolved fluorescence anisotropy with ~ 100 fs time resolution, found that the ultrafast decay component in the anisotropy showed a strong dependence on excitation/detection wavelength. The sub-picosecond decay anisotropy decay was seen in trimers of APC and C-PC and not in monomers, and, therefore, this fast decay has been attributed to pairwise excitation transfer among chromophores on different monomers of APC and C-PC.

© 1994 Optical Society of America