TY  - JOUR
A1  - Duan, Hong-Guang
A1  - Nalbach, Peter
A1  - Miller, R. J. Dwayne
A1  - Thorwart, Michael
T1  - Intramolecular vibrations enhance the quantum efficiency of excitonic energy transfer
T2  - Photosynthesis Research
N2  - We study the impact of underdamped intramolecular vibrational modes on the efficiency of the excitation energy transfer in a dimer in which each state is coupled to its own underdamped vibrational mode and, in addition, to a continuous background of environmental modes. For this, we use the numerically exact hierarchy equation of motion approach. We determine the quantum yield and the transfer time in dependence of the vibronic coupling strength, and in dependence of the damping of the incoherent background. Moreover, we tune the vibrational frequencies out of resonance with the excitonic energy gap. We show that the quantum yield is enhanced by up to 10% when the vibrational frequency of the donor is larger than at the acceptor. The vibronic energy eigenstates of the acceptor acquire then an increased density of states, which leads to a higher occupation probability of the acceptor in thermal equilibrium. We can conclude that an underdamped vibrational mode which is weakly coupled to the dimer fuels a faster transfer of excitation energy, illustrating that long-lived vibrations can, in principle, enhance energy transfer, without involving long-lived electronic coherence.
KW  - excitation energy transfer
KW  - vibronic coupling
KW  - efficiency of exciton transfer
Y1  - 2020
UR  - https://whge.opus.hbz-nrw.de/frontdoor/index/index/docId/3863
VL  - 144
IS  - 2
SP  - 137
EP  - 145
ER  -