Theoretical Challenges in Polaritonic Chemistry

TL;DR

Polaritonic chemistry explores how strong light-matter interactions in confined systems can alter chemical reactivity, requiring diverse multiscale theoretical tools to understand and predict phenomena across different experimental setups.

Contribution

This paper provides a comprehensive overview of the theoretical challenges and existing tools for modeling polaritonic chemistry across multiple scales.

Findings

Different cavity types influence light-matter coupling mechanisms.

Multiscale theoretical approaches are essential for accurate modeling.

Current tools have successes but also face significant challenges.

Abstract

Polaritonic chemistry exploits strong light-matter coupling between molecules and confined electromagnetic field modes to enable new chemical reactivities. In systems displaying this functionality, the choice of the cavity determines both the confinement of the electromagnetic field and the number of molecules that are involved in the process, whereas in wavelength-scale optical cavities light-matter interaction is ruled by collective effects, plasmonic subwavelength nanocavities allow even single molecules to reach strong coupling. Due to these very distinct situations, a multiscale theoretical toolbox is then required to explore the rich phenomenology of polaritonic chemistry. Within this framework, each component of the system (molecules and electromagnetic modes) needs to be treated in sufficient detail to obtain reliable results. Starting from the very general aspects of light-molecule interactions in typical experimental setups, we underline the basic concepts that should be taken into account when operating in this new area of research. Building on these considerations, we then provide a map of the theoretical tools already available to tackle chemical applications of molecular polaritons at different scales. Throughout the discussion, we draw attention to both the successes and the challenges still ahead in the theoretical description of polaritonic chemistry.