  The field of vibrational polariton chemistry was firmly established in 2016
when a chemical reaction rate at room temperature was modified within a
resonantly tuned infrared cavity without externally driving the system. Despite
intense efforts by scientists around the world to understand why the reaction
rate changes, no convincing theoretical explanation exists. In this
perspective, first, we briefly review this seminal experiment, as well as
relevant experiments that have since followed that have hinted at the roles of
reactant concentration, cavity frequency, and symmetry. Then, we analyze the
relevance of leading theories, such as quantum electrodynamics-modified
transition rate theories, the photonic solvent cage effect, the impact of
dissipation from dark states, bond strengthening via intramolecular vibrational
energy redistribution, and collectively enhanced local molecular properties.
Finally, we construct a roadmap toward the theory of vibrational polariton
chemistry by suggesting experiments to test theories and new paths for
theorists. We believe that understanding the importance of the onset of the
strong coupling regime, designing experiments to capture changes in reaction
pathways, and further developing the theories of cavity-modified intramolecular
vibrational energy redistribution and collectively enhanced local molecular
properties are crucial next steps. We hope this perspective will be a valuable
resource for guiding research in the field of vibrational polariton chemistry.
