Relation between Structure and Functionality in Photosynthetic Antenna Complex of Green Sulfur Bacteria: Efficiency under Natural Sunlight Pumping

. Our analysis shows that under natural sunlight, in photosynthetic antennae of GSB, the number of excitations reaching the RC per unit time matches the RC closure rate, and the internal efficiency shows values close to ∼80%. We also considered cylindrical structures where the orientation of the dipoles does not reflect the natural one. Specifically, we vary continuously the angle of the transition dipole with respect to the cylinder's main axis, focusing on the case where all dipoles are parallel to the cylinder axis. We also consider the important case where the dipoles are randomly oriented. In all cases, the light-harvesting efficiency is lower than in the natural structure, showing the high sensitivity of light harvesting to the specific orientation of the dipole moments. Our results provide a better understanding of the relationship between structure and functionality in natural photosynthetic antennae of green sulfur bacteria and could drive the design of efficient light-harvesting devices.