Velocity Distributions of Forward Moving Fragments in Heavy-Ion Collisions at Fermi Energies

Heavy-ion-induced projectile fragmentation reactions at Fermi energies are of interest to investigate the properties of nuclei far from the valley of stability, nuclear potentials, to get knew knowledge about nuclear equation of state. Isotopes far from stability line can be useful for various applications. It is therefore of interest to predict relative yields of isotopes and their energies with high precision. Here we treat such reactions in a microscopic approach, which consists of several steps: initialization of ground states of the colliding nuclei, dynamical evolution until the freeze-out point where the primary fragments can be identified, calculation of the excitation energy of the primary fragments, and their de-excitation. For the dynamical evolution we use a Boltzmann–Vlasov type transport equation, and for the de-excitation a statistical multifragmentation description. We apply this approach to collisions of projectile nuclei ^40 Ar with the target ^9 Be at energy 36.5 MeV per nucleon, calculate isotope distributions and velocity spectra of the produced isotopes and compare the results of our calculations to experimental data obtained at COMBAS set-up in JINR.