An efficient time-domain implementation of the multichromophoric Forster resonant energy transfer method

The excitation energy transfer (EET) process for photosynthetic antenna complexes consisting of subunits, each comprised of multiple chromophores, remains challenging to describe. The multichromophoric Forster resonance energy transfer theory is a popular method to describe the EET process in such systems. This paper presents a new time-domain method for calculating energy transfer based on the combination of multichromophoric Forster resonance energy transfer theory and the Numerical Integration of the Schrodinger Equation method. After validating the method on simple model systems, we apply it to the Light-Harvesting antenna 2 (LH2) complex, a light harvesting antenna found in purple bacteria. We use a simple model combining the overdamped Brownian oscillators to describe the dynamic disorder originating from the environmental fluctuations and the transition charge from the electrostatic potential coupling model to determine the interactions between chromophores. We demonstrate that with this model, both the calculated spectra and the EET rates between the two rings within the LH2 complex agree well with experimental results. We further find that the transfer between the strongly coupled rings of neighboring LH2 complexes can also be well described with our method. We conclude that our new method accurately describes the EET rate for biologically relevant multichromophoric systems, which are similar to the LH2 complex. Computationally, the new method is very tractable, especially for slow processes. We foresee that the method can be applied to efficiently calculate transfer in artificial systems as well and may pave the way for calculating multidimensional spectra of extensive multichromophoric systems in the future.

Automated summary

This paper presents a new time-domain method for calculating energy transfer in photosynthetic antenna complexes based on the combination of multichromophoric Forster resonance energy transfer theory and the Numerical Integration of the Schrodinger Equation method. The method accurately describes the energy transfer rate for biologically relevant multichromophoric systems similar to the LH2 complex. This method has computational tractability and may have potential applications in calculating transfer in artificial systems. Overall, it receives a score of 8 out of 10.