Microscopic calculation of pre-equilibrium emission

Previous TDHF calculations have shown that a pre-equilibrium emission of nucleons should be seen for asymmetric collisions of nuclei. Recent calculations indicate that the added effect of two-body collisions is to enhance this pre-equilibrium emission, it being seen also for symmetric collisions. More detailed calculations of this phenomenon are presenied here. The two-body collisions are treated by the time-relaxation method. This method is reviewed, and a revised formula for the relaxation time is introduced.Calculations are made in a slab geometry. For real nuclei, as much as 6% of all nucleons are estimated to be emitted at a beam energy of E_c.m. = 20 MeV/A. The energy distribution of the emitted nucleons relates to a temperature of 13 MeV at this energy. At 5 MeV/A, the emission is reduced to about 1 %.