To further examine the interesting PMET dependence on λ D , Fig. time populations are affected not only by the effective forward rate constants shown in Fig. and Fig. but by the effective backward rate constants as well. Simulations with similar forward rate constants but different backward rate constants can have different long-time populations such that the simulation with a larger backward rate constant can have a smaller long-time acceptor population than the simulation with a smaller backward rate constant. Fig. , like Fig. , does not show a strong dependence on λ D due to the small rate of transfer to the dark states and, as a result, the long-time acceptor populations are all nearly 1 for all simulated Q and λ D .