Cavity-modified nonequilibrium Fermi's golden rule rate coefficients from cavity-free inputs

Area of Science:

• Physical Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• The Nonequilibrium Fermi's Golden Rule (NE-FGR) is a theoretical tool for calculating charge transfer (CT) rates.
• NE-FGR is particularly useful when nuclear degrees of freedom are in a nonequilibrium initial state.

Purpose of the Study:

• To investigate how electromagnetic microcavities affect NE-FGR rates.
• To develop a simplified method for calculating cavity-modified NE-FGR rates.
• To introduce an approximation termed cavity-modified instantaneous Marcus theory.

Main Methods:

• Theoretical framework based on NE-FGR.
• Analysis of weak coupling between molecular systems and cavity modes.
• Development of a method to estimate cavity-modified rates from existing inputs.
• Application to specific molecular systems (carotenoid-porphyrin-C60 triad, Garg-Onuchic-Ambegaokar model).

Main Results:

• NE-FGR rates are significantly modified by microcavities, even with weak coupling.
• Cavity-modified NE-FGR rates can be estimated using inputs for cavity-free calculations.
• A new approximation, cavity-modified instantaneous Marcus theory, is introduced.

Conclusions:

• Electromagnetic microcavities offer a way to tune charge transfer dynamics.
• The proposed theoretical framework simplifies the calculation of cavity-modified CT rates.
• The findings are applicable to photo-induced CT in complex molecular systems and condensed phase reactions.