Light-matter interaction governs a vast array of physical and chemical phenomena. While traditional effects like fluorescence occur in the weak coupling regime, placing molecules within the confined electromagnetic environment of a nanocavities can fundamentally alter molecular properties. When the coupling strength exceeds the system's decay rates, the system enters the strong coupling regime. In this state, light and matter hybridize to form polaritons. In these hybrid states, where molecular properties are modified significantly, similarly to how atomic orbitals are during the formation of a chemical bond. Since the Ebbesen group’s landmark demonstration of altered reaction kinetics in spiropyran, the field has expanded rapidly, showcasing control over processes like triplet-triplet annihilation. Despite these successes, the underlying mechanisms of polaritonic chemistry remain a subject of intense debate.
In this seminar, I will provide an introduction to the field and detail the recent theoretical developments from our research group. We combine quantum optics, traditional chemical dynamics, and electronic structure theory to provide a theoretical framework for polaritonic chemistry. I will specifically explore our developments in ab initio polaritonic chemistryandits implications for ground-state molecular properties as well as our studies in photochemical control by means of strong light-matter coupling.