Charge and exciton transport in organic semiconductors is crucial for a variety of optoelectronic applications. The prediction of the material-dependent exciton diffusion length and the charge carrier mobility is a prerequisite for tailoring new materials for organic electronics. At room temperature often a hopping process can be assumed. In this work, three hopping models based on Fermi's Golden rule but with different levels of approximation-the spectral overlap approach, the Marcus theory, and the Levich-Jortner theory-are compared for the calculation of charge carrier mobilities and exciton diffusion lengths for oligoacenes, using the master equation approach and Monte Carlo simulations. Efor the donor deexcitation/neutralization and the analogue equation for the acceptor excitation/ionization respectively, the hopping rate, Eq. (1), can be written aswith the Franck-Condon weighted density of states (FCWD) 40,41,43WIREs Computational Molecular Science Prediction of charge and energy transport in oligoacenes using rate constant expressions Volume 6, November/December 2016Here, a linear approximation for e J E AD ð Þ is used, where J 0 : = d e J E AD ð Þ=dE AD j E AD = 0 and J : = e J 0 ð Þ, and thereforeEq. (14), the difference vector Δd ! of the equilibrium structures of the charged/excited state and the neutral/ground state is determined. This vector is transformed from Cartesian coordinates into a vector Δq ! in the normal mode basis viawhere the matrix A contains the normal mode vectors. The molecular vibrations are treated as harmonic oscillators. 50,55 Therefore, the relaxation Advanced Review