Shining Light on the Microscopic Resonant Mechanism Responsible for Cavity-Mediated Chemical Reactivity

TL;DR

This paper uses quantum-electrodynamical density-functional theory to reveal how cavity-induced vibrational strong light-matter coupling can inhibit chemical reactions by redistributing vibrational energy, providing microscopic insight into cavity-mediated reactivity.

Contribution

It uncovers the microscopic mechanism behind reduced reaction rates in cavity environments, highlighting the role of vibrational mode mediation and energy redistribution.

Findings

Multiple resonances observed in the reaction process

Cavity mode mediates vibrational energy redistribution

Inhibition of reaction due to energy localization changes

Abstract

Strong light-matter interaction in cavity environments is emerging as a promising approach to control chemical reactions in a non-intrusive and efficient manner. The underlying mechanism that distinguishes between steering, accelerating, or decelerating a chemical reaction has, however, remained unclear, hampering progress in this frontier area of research. We leverage quantum-electrodynamical density-functional theory to unveil the microscopic mechanism behind the experimentally observed reduced reaction rate under cavity induced resonant vibrational strong light-matter coupling. We observe multiple resonances and obtain the thus far theoretically elusive but experimentally critical resonant feature for a single strongly-coupled molecule undergoing the reaction. While we do not explicitly account for collective coupling or intermolecular interactions, the qualitative agreement with experimental measurements suggests that our conclusions can be largely abstracted towards the experimental realization. Specifically, we find that the cavity mode acts as mediator between different vibrational modes. In effect, vibrational energy localized in single bonds that are critical for the reaction is redistributed differently which ultimately inhibits the reaction.