Abstract
An extended time-dependent Hartree-Fock theory which incorporates the effects of nucleon-nucleon collisions into the mean field is presented and applied to head-on collisions of O16 +16O at low incident energies. Particularly investigated is the influence of nucleon-nucleon collisions on the low angular momentum limit for fusion which is predicted by time-dependent Hartree-Fock calculations. It is found that the threshold energy for the low angular momentum limit is dramatically increased because of nucleon-nucleon collision effects.