Insights into photosynthetic energy transfer gained from free-energy structure: Coherent transport, incoherent hopping, and vibrational assistance revisited

Abstract

Giant strides in ultrashort laser pulse technology have enabled real-time observation of dynamical processes in complex molecular systems. Specifically, the discovery of oscillatory transients in the two-dimensional electronic spectra of photosynthetic systems stimulated a number of theoretical investigations exploring possible physical mechanisms of the remarkable quantum efficiency of light harvesting processes. However, the theories employed have reached a high degree of sophistication and have become complex, making it difficult to gain insights into microscopic processes and biologically significant questions. In this work, we revisit the elementary aspects of environment-induced fluctuations in the involved electronic energies and present a simple way to understand energy flow with the intuitive picture of relaxation in a funnel-type free-energy landscape. The presented free-energy description of energy transfer reveals that typical photosynthetic systems operate in an almost barrierless regime. The approach also provides insights into the distinction between coherent and incoherent energy transfer and criteria by which the necessity of the vibrational assistance is considered.

References in corpus (14)

• Environment-Assisted Quantum Walks in Photosynthetic Energy Transfer
• Dephasing assisted transport: Quantum networks and biomolecules
• Environment-Assisted Quantum Transport
• Highly efficient energy excitation transfer in light-harvesting complexes: The fundamental role of noise-assisted transport
• Efficiency of energy transfer in a light-harvesting system under quantum coherence
• The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae
• Correlation-dependent coherent to incoherent transitions in resonant energy transfer dynamics
• Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra
• Vibrational wave packet induced oscillations in two-dimensional electronic spectra. I. Experiments
• Vibrational wave packet induced oscillations in two-dimensional electronic spectra. II. Theory
• Effects of Herzberg--Teller vibronic coupling on coherent excitation energy transfer
• Linear, third- and fifth-order nonlinear spectroscopy of a charge transfer system coupled to an underdamped vibration
• An exciton-coupled electron transfer process controlled by non-Markovian environments
• Structure-Dynamics Relation in Physically-Plausible Multi-Chromophore Systems

Cited by in corpus (4)

• A simple generalization of the energy gap law for nonradiative processes
• Hidden Vibronic and Excitonic Structure and Vibronic Coherence Transfer in the Bacterial Reaction Center
• Simulating Photosynthetic Energy Transport on a Photonic Network
• Interplay of vibration- and environment-assisted energy transfer