A Reaction Kinetic Model for Vacuum-Field Catalysis Based on Vibrational Light-Matter Coupling
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Since conventional catalysts are materials-based, they are effective only for particular chemical reactions. Recent studies suggest that vacuum-field catalysis (or cavity catalysis) based on vibrational light-matter coupling can boost reactions without the above constraint. Herein, we propose a reaction kinetic model for such vacuum-field-catalyzed reactions. Vibrational light-matter coupling is an interaction in which a molecular vibration and infrared (IR) vacuum field are coupled in resonance, consequently creating a pair of Rabi-split vibro-polaritonic states. Our kinetic model hypothesizes that vibrational light-matter coupling reshapes the reaction potential surface, thereby changing its reaction barrier height. We translate such a qualitative picture into two kinds of analytical equations derived from the Arrhenius and Eyring–Polanyi theories: both the equations are obtained as a function of the coupling ratio ΩR/2ω0 of vibro-polaritons (ΩR: Rabi frequency between a pair of vibro-polaritons, ω0: vibrational frequency of reactants), indicating that ΩR/2ω0 is a decisive quantity to define the catalytic activity of vacuum-field catalysis. Our numerical calculation shows that when ΩR/2ω0 ≥ 0.1, reactions may be accelerated by several orders of magnitude. Most importantly, our kinetic model can account well for rate enhancements ranging from ~100 to ~104 observed for vacuum-field-catalyzed reactions. We expect that our findings will bring fresh perspectives not only to chemistry but also to the broad fields of science and technology.