Many-Molecule Reaction Triggered by a Single Photon in Polaritonic Chemistry.

The second law of photochemistry states that, in most cases, no more than one molecule is activated for an excited-state reaction for each photon absorbed by a collection of molecules. In this Letter, we demonstrate that it is possible to trigger a many-molecule reaction using only one photon by strongly coupling the molecular ensemble to a confined light mode. The collective nature of the resulting hybrid states of the system (the so-called polaritons) leads to the formation of a polaritonic "supermolecule" involving the degrees of freedom of all molecules, opening a reaction path on which all involved molecules undergo a chemical transformation. We theoretically investigate the system conditions for this effect to take place and be enhanced.