Abstract
The significance of absorption kinetics data in distinguishing between two-step and virtual mechanisms for the primary charge separation in reaction centers of photosynthetic bacteria is examined. A simple class of models is presented in which the transfer may occur predominantly by a virtual process and in which the intermediate state develops some small, but nonzero, transient population. The simplicity of the model allows both the virtual and two-step contributions to the intermediate state population to be easily calculated. We find that the peak intermediate state population can be either close to 1 or very small (<10-2), depending on the system parameters such as electronic matrix elements, the energy denominator, and the lifetimes and dephasing rates in the electronic states. In particular, purely virtual transfer can yield a peak intermediate-state population of 10%. These calculations imply that observation of a small amount of bleaching in the bacteriochlorophyll monomer band does not necessarily rule out a virtual process.
Original language | English (US) |
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Pages (from-to) | 6242-6247 |
Number of pages | 6 |
Journal | Journal of physical chemistry |
Volume | 95 |
Issue number | 16 |
DOIs | |
State | Published - 1991 |
All Science Journal Classification (ASJC) codes
- General Engineering
- Physical and Theoretical Chemistry