화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.119, No.18, 5755-5764, 2015
Efficient Pathways of Excitation Energy Transfer from De localized S-2 Excitons in the Peridinin-Chlorophyll a-Protein Complex
Excitation energy transfer (EET) in peridinin-chlorophyll-protein (PCP) complexes is dominated by the S-1 -> Q(y) pathway, but the high efficiencies cannot be solely explained by this one pathway. We postulate that EET from peridinin S-2 excitons may also be important. We use complete active space configuration interaction calculations and the transition density cube method to calculate Coulombic couplings between peridinin and chlorophyll a in the PCP complex of the dinoflagellate Amphidinium carterae and compare monomeric and dimeric delocalized peridinin S-2 excited states. Our calculations show that the S-2 -> Q(y) EET pathway from peridinin to chlorophyll a is the dominant energy transfer pathway from the S-2 excited state in PCP, with several values in the sub-picosecond range. This result suggests that the S-2 -> Q(y) EET pathway may be responsible for the reported chlorophyll a bleaching signature seen in experiment at around 200 fs, and not the S-2 -> Q(x) pathway as previously suggested.