Langevin approach to heavy-ion fusion cross sections and spin distributions above and below the barrier

Recent experimental data concerning fusion cross sections, spin distributions and their moments are analysed in the framework of a transport model by solving Langevin equations based on the surface friction model. Experiment and theory are in good agreement at energies above the fusion barrier. Below the barrier a modification of the Einstein relation again yields satisfactory results for fusion-evaporation systems but there remain large discrepancies for in the case of fusion-fission systems. (orig.)