where 𝑘 0 is the chemical reaction rate constant outside the cavity, and 𝑘 VSC accounts for the pure cavityinduced effect. As this is a thermally activated reaction, there already exist some excited-state populations and transitions outside the cavity, which 𝑘 0 accounts for. Note that Eq. 11 assumes that the pure cavity effect 𝑘 VSC can be added with 𝑘 0 , which is a fundamental assumption in the current theory.