Shared-mode assisted resonant energy transfer in the weak coupling regime

Area of Science:

• Physical Chemistry
• Spectroscopy
• Quantum Dynamics

Background:

• Correlated chromophore environments can influence excitation transfer dynamics.
• The standard Förster resonance energy transfer (FRET) model assumes independent chromophore environments.
• Weakly interacting donor and acceptor chromophores coupled to shared vibrational modes challenge the standard FRET model.

Purpose of the Study:

• To theoretically derive the dependence of the FRET rate on shared vibrational mode structure and coupling.
• To re-evaluate the FRET rate when electronic excitations couple to common vibrational modes.
• To provide a quantitative calculation for a system of current interest.

Main Methods:

• Theoretical derivation of the FRET rate considering correlated environments.
• Renormalization of phonon reorganization energy to account for excitation-vibration couplings.
• Examination of simplified Gaussian lineshapes and quantitative calculation for a specific system.

Main Results:

• The standard FRET rate formula is shown to break down under correlated environmental conditions.
• A renormalized phonon reorganization energy is introduced, incorporating the magnitude and sign of excitation-vibration couplings.
• The study quantifies the impact of shared modes on FRET rates for a relevant system.

Conclusions:

• Environmental correlations significantly impact excitation transfer dynamics in FRET.
• A modified theoretical framework is necessary for accurate FRET rate calculations in systems with shared vibrational modes.
• The findings offer a more comprehensive understanding of energy transfer in complex molecular systems.