  Light-matter interaction not only plays an instrumental role in
characterizing materials' properties via various spectroscopic techniques but
also provides a general strategy to manipulate material properties via the
design of novel nanostructures. This perspective summarizes recent theoretical
advances in modeling light-matter interactions in chemistry, mainly focusing on
plasmon and polariton chemistry. The former utilizes the highly localized
photon, plasmonic hot electrons, and local heat to drive chemical reactions. In
contrast, polariton chemistry modifies the potential energy curvatures of bare
electronic systems, and hence their chemistry, via forming light-matter hybrid
states, so-called polaritons. The perspective starts with the basic background
of light-matter interactions, molecular quantum electrodynamics theory, and the
challenges of modeling light-matter interactions in chemistry. Then, the recent
advances in modeling plasmon and polariton chemistry are described, and future
directions toward multiscale simulations of light-matter interaction-mediated
chemistry are discussed.
