(small detuning of donor state energy E D j versus E D j ′ ̸ = j at R RC +A j (X = 0) relative to collective coupling strength to ensure the UP eigenstate has significant character |c +, j | 2 ≈ sin 2 Φ/N of state |D j ⟩ in order to couple to state |A j ⟩ at R RC +A j (X = 0)). When any of the parameters λ D , Γ, or V l are non-zero (see Fig. ), the dynamics of the polariton and acceptor states are affected by factors beyond those of the PMET rates in Eq. 28. More specifically, a non-zero λ D can allow for dynamical disorder among the polariton states which causes population transfer between the UP, LP, and dark states; a finite value of Γ causes population decay from photonic polariton states to |G, 0⟩; and V l causes population transfer between |G, 0⟩ and photonic polariton states. While these factors create challenges for describing the population dynamics of the polariton and acceptor states with analytic expressions, explicit quantum dynamics simulations of the molecular-cavity system can provide these population dynamics beyond the limitations of analytic expressions. In this work, we calculate effective rate constants between the donor manifold of states (|G, 0⟩ and the polariton states) and the acceptor manifold of states ({|A j ⟩}) by fitting the simulated explicit population dynamics of the acceptor states to a simple two-state ET model with fitted forward and backward rate constants. In particular, for a system initialized among the donor manifold of states, we fit the simulated population dynamics of the acceptor states ρ {A} (t) ≡ ∑ j ⟨A j | ρ(t)|A j ⟩ to the following equation