Simulation of photochemical hole-burning experiments on photosynthetic reaction centers.

An effective Hamiltonian formalism is used to calculate the homogeneous linewidth of long-wavelength absorption in the photosynthetic reaction center. Agreement with the experimental values of approximately 400 cm(-1) for the hole width of the 990-nm band of Rhodopseudomonas viridis is obtained. The anomalously (two orders of magnitude) large width is explained in terms of resonant coupling to charge transfer states. These results support a dynamical model of primary charge separation [Friesner, R. & Wertheimer, R. (1982) Proc. Natl. Acad. Sci USA 79, 2138-2142] in which such resonant coupling was also concluded to be important.