Polaritonic Chemistry
In recent years, experiments have reported that reaction rates can be modified by placing a pair of mirrors around the reaction mixture (forming a microcavity). This results in strong coupling between molecular vibrations and light modes, which is signified by a splitting of a line in the IR spectrum — the Rabi splitting. This spectral change is well-understood, but how it results in a change in reactivity is still an open question.
In our group, we try to tackle this problem in multiple ways. On the one hand, we run fully quantum-mechanical simulations (based on open quantum system theory) to gain insight into the reactive dynamics that takes places under strong coupling. On the other hand, we try expand our view — we have for example investigated how important quantum effects are, and have worked on lifting some approximations that are typically taken. In particular, we have studied the importance of changes in the electronic ground state due to the coupling to the cavity, and looked into going beyond the single-mode approximation by including the entire continuum of electromagnetic field modes.
In the end, we hope to understand the mechanism by which a cavity can modify reaction rates. We expect that this will teach us something about the fundamental aspects of chemical reactions, and in the end this may also help us guide experiment: in the future, it may allow us to steer chemical reactions in a more economical and green way.