Potential gradient parametrization in a Langevin type dissipative dynamics

A parametrization of the conservative force in the dynamical coalescence an d reseparation model is proposed. This model with one body dissipation form ula, Yukawa plus exponential finite range potential, and shell effects incl uded was recently adopted to follow Langevin trajectories for a collision o f two very heavy nuclei which can end up as a compound system or reseparate . With our parametrization it is possible to speed up model calculations by a factor of 10 without leasing accuracy of trajectory integration. This ca n be of some importance in a case of Langevin trajectories calculation wher e many of them have to be traced in order to estimate probability for a pro cess of interest, namely a fusion of two very heavy nuclei at beam energies close to the Coulomb barrier. Few examples of fusion excitation functions of heavy nuclei calculated with this faster version of the computer code ar e presented.