Light-harvesting system 2 (LH2) executes the primary processes of photosynthesis in purple bacteria; photon absorption and energy transportation to the reaction centre. A detailed mechanistic insight into these operations is obscured by the complexity of the light-harvesting systems, particularly by the chromophore-environment interaction. In this work, we focus on the effects of the protein residues that are ligated to the bacteriochlorophylls (BChls), and construct potential energy surfaces of the ground and first optically-excited state for the various BChl-residue systems, where we in each case consider two degrees of freedom in the intermolecular region. We find that the excitation energies are only slightly affected by the considered modes. In addition, we see that axial ligands and hydrogen-bonded residues have opposite effects on both excitation energies and oscillator strengths, by comparing to the isolated BChls. Our results indicate that only a small part of the chromophore-environment interaction can be associated with the intermolecular region between a BChl and an adjacent residue, but that it may be possible to selectively raise or lower the excitation energy at the axial and planar residue positions, respectively.
Scheda prodotto non validato
Scheda prodotto in fase di analisi da parte dello staff di validazione
|Titolo:||Intermolecular Modes Between LH2 Bacteriochlorophylls and Protein Residues; the Effect on the Excitation Energies|
|Appare nelle tipologie:||1.1 Articolo in rivista|
File in questo prodotto: