Ultrafast singlet excitation transfer from carotenoids to chlorophylls via different pathways in light-harvesting complex II of higher plants

Sub-picosecond excitation transfer from carotenoids to chlorophyll in light-harvesting complex II was studied at 77 K using pump-probe experiments. We did not find evidence for energy transfer from the carotenoids to chlorophyll b. However, transfer from carotenoid to chlorophyll a was found to occur with a time constant of 220±25 fs. It is observed that spectrally different chlorophyll a pools are populated upon selective excitation of different carotenoids.