Vibration-assisted resonance in photosynthetic excitation energy transfer

TL;DR

This paper explores how intramolecular vibrations facilitate resonance, enhancing the efficiency and directionality of energy transfer in photosynthetic systems through a microscopic mechanism.

Contribution

It introduces a new analytical model showing how vibrational modes create resonant pathways, improving energy transfer efficiency and directionality in photosynthesis.

Findings

Vibrational states support fast energy transport.

Resonances between vibrational and excitonic levels enhance efficiency.

Vibrational damping provides intrinsic energy flow directionality.

Abstract

Understanding how the effectiveness of natural photosynthetic energy harvesting systems arises from the interplay between quantum coherence and environmental noise represents a significant challenge for quantum theory. Recently it has begun to be appreciated that discrete molecular vibrational modes may play an important role in the dynamics of such systems. As an alternative to computationally demanding numerical approaches, we present a microscopic mechanism by which intramolecular vibrations contribute to the efficiency and directionality of energy transfer. Excited vibrational states create resonant pathways through the system, supporting fast and efficient energy transport. Vibrational damping together with the natural downhill arrangement of molecular energy levels gives intrinsic directionality to the energy flow. Analytical and numerical results demonstrate a significant enhancement of the efficiency and directionality of energy transport that can be directly related to the existence of resonances between vibrational and excitonic levels.