Abstract

Time-resolved experiments on reaction centers of rhodopseudomonas viridis reveal (during the first 5 ps after excitation of the Q_x transition of the special pair at 620 nm) several intermediate states with different absorption properties, (1) Rapid bleaching and a subsequent absorption increase occur at λ = 620 nm within 150 fs. This finding indicates formation of the excited electronic state and a rapid charge separation in the special pair. (2) A relative absorption decrease with a time constant of ~ 1 ps may be due to an electron transfer to an accessory bacteriochlorophyl. (3) An absorption increase with a 5-ps time constant is related to the transfer of an electron to the bacteriopheophytine.

© 1986 Optical Society of America