Quantum Interferences
and Electron Transfer in Photosystem
I
Nicolas Renaud
Daniel Powell
Mahdi Zarea
Bijan Movaghar
Michael R. Wasielewski
Mark A. Ratner
10.1021/jp308216y.s001
https://acs.figshare.com/articles/journal_contribution/Quantum_Interferences_and_Electron_Transfer_in_Photosystem_I/2392942
We have studied the electron transfer occurring in the
photosystem
I (PSI) reaction center from the special pair to the first ironâ€“sulfur
cluster. Electronic structure calculations performed at the DFT level
were employed to determine the on-site energies of the fragments comprising
PSI, as well as the charge transfer integrals between neighboring
pairs. This electronic Hamiltonian was then used to compute the charge
transfer dynamics, using the stochastic surrogate Hamiltonian approach
to account for the coherent propagation of the electronic density
but also for its energy relaxation and decoherence. These simulations
give reasonable transfer time ranging from subpicoseconds to nanoseconds
and predict coherent oscillations for several picoseconds. Due to
these long-lasting coherences, the propagation of the electronic density
can be enhanced or inhibited by quantum interferences. The impact
of random fluctuations and asymmetries on these interferences is then
discussed. Random fluctuations lead to a classical transport where
both constructive and destructive quantum interferences are suppressed.
Finally it is shown that an energy difference of 0.15 eV between the
on-site energies of the phylloquinones leads to a highly efficient
electron transfer even in presence of strong random fluctuations.
2016-02-19 02:41:58
charge transfer dynamics
charge transfer integrals
quantum interferences
electron transfer
density
Electronic structure calculations
Hamiltonian
DFT
PSI
fluctuation
propagation