Intramolecular reorganization energies and Franck-Condon integrals for ET from pheophytin to quinone in bacterial photosynthetic reaction centers

Intramolecular reorganization energies and Franck-Condon integrals of two redox cofactors of bacterial photosynthetic reaction centers have been evaluated by DFT computations of the optimum geometries and vibrational frequencies of the normal and reduced forms. The intramolecular modes which play a major role in electron transfer dynamics have been identified by Duschinsky's analysis and the Franck-Condon integrals have been computed by using the whole set of normal coordinates of the acceptor and donor groups, in order to reliably account both for shifts, mix, and frequency change of the normal coordinates.