Molecular Chemistry in Cavity Strong Coupling

Abstract

The coherent exchange of energy between materials and optical fields leads to strong light−matter interactions and so-called polaritonic states with intriguing properties, halfway between light and matter. Two decades ago, research on these strong light−matter interactions, using optical cavity (vacuum) fields, remained for the most part the province of the physicist, with a focus on inorganic materials requiring cryogenic temperatures and carefully fabricated, high-quality optical cavities for their study. This review explores the history and recent acceleration of interest in the application of polaritonic states to molecular properties and processes. The enormous collective oscillator strength of dense films of organic molecules, aggregates, and materials allows cavity vacuum field strong coupling to be achieved at room temperature, even in rapidly fabricated, highly lossy metallic optical cavities. This has put polaritonic states and their associated coherent phenomena at the fingertips of laboratory chemists, materials scientists, and even biochemists as a potentially new tool to control molecular chemistry. The exciting phenomena that have emerged suggest that polaritonic states are of genuine relevance within the molecular and material energy landscape.

Collective Strong Coupling Modifies Aggregation and Solvation

“…The coherent interaction of molecules with confined optical modes leads to hybrid light–matter states called polaritons. − In the strong coupling regime, usually achieved by coupling several molecules to the optical cavity, experiments show significant modifications of chemical properties. − As a result of their delocalized nature, polaritons in quantum optics are studied from a collective perspective where the molecules are modeled as few-level systems that indirectly interact solely through the photon field. − However, chemistry is governed by local interactions, and the molecular complexity requires refined chemical methods to analyze processes like reactions. The behavior of molecules is, hence, susceptible to their immediate surroundings.…”

Variational Lang–Firsov Approach Plus Møller–Plesset Perturbation Theory with Applications to Ab Initio Polariton Chemistry

“…A polaron is a quasiparticle consisting of an electron and its surrounding lattice deformation (phonons), whereas a polariton is a quasiparticle resulting from the strong coupling between matter excitations, such as excitons and photons. Historically, the polaron problem has been a classic topic in condensed matter physics and plays a key role in various important phenomena, including charge transport (mobility), magnetism, and superconductivity. , Recently, cavity-mediated chemical reactions have attracted renewed attention to polaritons, where experimental claims have been put forward that chemical reaction rates and pathways can be manipulated by the formation of polaritons in an optical cavity, − potentially providing a new dimension for fine control of chemical processes. ,− …”

Vibrational Alchemy of DNA: Exploring the Mysteries of Hybridization under Cooperative Strong Coupling with Water

“…Furthermore, the emergence of these hybrid states alters the hydration structure of water within aqueous mixtures, impacting the coupling behavior of water molecules and even enhancing the ionic conductivity of the solution. , Regarding the strength of the VSC effect, the collective coupling of a large number of reactant molecules to the optical cavity mode is often required to achieve a large Rabi splitting, which is positively proportional to the square root of the number of reactant molecules. ,− However, this is limited by the solubility and concentration of the reactants. The feasibility using an alternative solution to achieve VSC has been demonstrated by the solvent-based cooperative coupling strategy. , This cooperative VSC effect produces when the reactants share at least one common group with the solvent molecules, thus influencing the reaction kinetics. , …”