Reaction mechanisms in heavy ion fusion

Abstract

Abstract. We discuss the reaction mechanisms involved in heavy ion fusion. We begin with collisions of tightly bound systems, considering three energy regimes: energies above the Coulomb barrier, energies just below the barrier and deep sub-barrier energies. We show that channel coupling effects may influence the fusion process at above-barrier energies, increasing or reducing the cross section predicted by single barrier penetration model. Below the Coulomb barrier, it enhances the cross section, and this effect increases with the system's size. It is argued that this behavior can be traced back to the increasing importance of Coulomb coupling with the charge of the collision partners. The sharp drop of the fusion cross section observed at deep sub-barrier energies is addressed and the theoretical approaches to this phenomenon are discussed. We then consider the reaction mechanisms involved in fusion reactions of weakly bound systems, paying particular attention to the calculations of complete and incomplete fusion available in the literature.

Examining the role of transfer coupling in sub-barrier fusion ofTi46,50+Sn124

“…Heavy-ion fusion near the Coulomb barrier continues to attract experimental and theoretical interest [1]. The enhanced fusion cross sections at sub-barrier energies, with respect to a one-dimensional barrier penetration model, can be described by the coupling of the relative motion to the internal degrees of freedom of the participants.…”