Photosynthetic apparatus of purple bacteria.

3. Excitation transfer in the PSU 18 3.1 Electronic excitations of BChls 22 3.1.1 Individual BChls 22 3.1.2 Rings of BChls 22 3.1.2.1 Exciton states 22 3.1.3 Effective Hamiltonian 24 3.1.4 Optical properties 25 3.1.5 The effect of disorder 26 3.2 Theory of excitation transfer 29 3.2.1 General theory 29 3.2.2 Mechanisms of excitation transfer 32 3.2.3 Approximation for long-range transfer 34 3.2.4 Transfer to exciton states 35 3.3 Rates for transfer processes in the PSU 37 3.3.1 Car U BChl transfer 37 3.3.1.1 Mechanism of Car U BChl transfer 39 3.3.1.2 Pathways of Car U BChl transfer 40 3.3.2 Efficiency of Car U BChl transfer 40 3.3.3 B800–B850 transfer 44 3.3.4 LH-II U LH-II transfer 44 3.3.5 LH-II U LH-I transfer 45 3.3.6 LH-I U RC transfer 45 3.3.7 Excitation migration in the PSU 46 3.3.8 Genetic basis of PSU assembly 49