Abstract
Femtosecond absorption spectroscopy was applied to study for the first time excitation dynamics in isolated photosystem I trimers from Arthrospira platensis, which display extremely long-wavelength absorption peaks. Pump–probe spectra observed at 77K in the timescale of dozens of picoseconds upon 70-fs excitation revealed two maxima near 710 and 730nm, which correspond to red chlorophyll forms. Bleaching at 680nm developed in ∼200fs, whereas the bleaching kinetics at 710 and 730nm exhibited two components with time constants of 1 and 5.5ps. Comparison of the kinetics of bleaching development at 710nm and 730nm with that of bleaching decay at 680nm indicated that both long-wavelength forms of trimers are populated mainly via direct energy transfer from bulk chlorophyll.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
