Ab initio calculations of the excited state properties of a portion of the LH2 complex consisting of a supermolecule of two B850 bacteriochlorophyll (BChl), one B800 BChl, and one rhodopin glucoside carotenoid show significant mixing between the BChl and carotenoid states. Calculation of the B800-B850 coulombic coupling, through the transition density cube method, both with and without the carotenoid reveal that the carotenoid affects an increase in the B800-B850 coupling via an indirect (superexchange) mechanism. This carotenoid-mediated coupling explains a portion of the difference between the B800-B850 energy transfer rate determined experimentally and through traditional (Förster) calculations.
|Published - Jul 20 1999
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry