Thus, total reorganization free energy can be divided into λ in and λ out , which correspond to the bond (inner) and solvation (outer) effects, respectively. We see that the explicit waters role (λ out ) to stabilize the reorganization energy is crucial. The two models behave similarly. Finally, as the number of water molecules increases, the value of the ET free energy with the explicit solvation model gradually decreases. But the ∆A 0 IJ value remains almost constant with the combined model. We see that the explicite-implicite solvation model is a better choice for this type of simulations.