Dissipative dynamics in quasi-fission

Abstract

Quasi-fission is the primary reaction mechanism that prevents the formation of superheavy elements in heavy-ion fusion experiments. Employing the time-dependent density functional theory approach we study quasi-fission in the systems ${}^{40,48}$Ca+${}^{238}$U. Results show that for ${}^{48}$Ca projectiles the quasi-fission is substantially reduced in comparison to the ${}^{40}$Ca case. This partly explains the success of superheavy element formation with ${}^{48}$Ca beams. For the first time, we also calculate the repartition of excitation energies of the two fragments in a dynamic microscopic theory. The system is found in quasi-thermal equilibrium only for reactions with ${}^{40}$Ca. The differences between both systems are interpreted in terms of initial neutron to proton asymmetry of the colliding partners.

Comments: 5 pages, 4 figures