Charge-transfer chemical reactions in nanofluidic Fabry-Pérot cavities

Abstract

We investigate the chemical reactivity of molecular populations confined inside a nanofluidic Fabry-P\'erot cavity. Due to strong light-matter interactions developing between a resonant electromagnetic cavity mode and the electric dipole moment of the confined molecules, a collective polariton excitation is formed. The former gets dressed by environmental vibrational and rotational degrees of freedom of the solvent. We call the resulting polariton dressed by its cloud of environmental excitation a ``reacton'', since it further undergoes chemical reactions. We characterize how the reacton formation modifies the kinetics of a photoisomerization chemical reaction involving an elementary charge-transfer process. We show that the reaction driving force and reorganization energy are both modulated optically by the reactant concentration, the vacuum Rabi splitting, and the detuning between the Fabry-P\'erot cavity frequency and targeted electronic transition. Finally, we compute the ultrafast picosecond dynamics of the whole photochemical reaction. We predict that despite optical cavity losses and solvent-mediated nonradiative relaxation, measurable signatures of the reacton formation can be found in state-of-the-art pump-probe experiments.