Unravelling the Mechanisms of Exciton Transport in Natural Light Harvesting Systems

Abstract

Photosynthetic organisms contain light harvesting complexes comprised of pigments that absorb sunlight as electronic excitations. In this work, the transfer of this exci- tation energy in four natural light harvesting complexes is investigated; specifically, LHCII and CP26 from higher plants, along with FMO and the chlorosome from Green Sulfur Bacteria. For the LHCII, CP26, and FMO complexes, the mechanistic details from two different starting locations for the initial excitation at two temperatures were extracted and discussed. In order to study the transport through the chlorosome, nat- ural and artificial nanotublar models were constructed to represent the arrangement of the pigments and details about the spread of the exciton are analyzed. This was all facilitated through the application of the approximate quantum-classical method known as the forward-backward trajectory solution (FBTS).