Ng c . Note that for the case λ D ̸ = 0, the disorderless |+⟩ state defined in Eq. 13a is not an exact eigenstate of Ĥpl but may instead be an approximation of an eigenstate whose expansion coefficients are similar to that of |+⟩ but whose acceptor couplings may differ from V +A j at R RC +A j (X = 0) and whose driving force may differ from ∆G +A j . For a thermal Boltzmann distribution of nuclear positions, this approximation should be reasonable when the donor energy disorder 87 2λ D k B T < √ Ng c /3 (low molecular disorder relative to collective coupling strength ) and ∆E 0