Survey of heavy-ion fusion hindrance for lighter systems

Abstract

A survey of heavy-ion fusion cross sections at extreme sub-barrier energies has been carried out for lighter systems with positive Q values. A general parametrization is proposed, which describes excitation functions for a wide range of light systems at low energies. This parametrization is then applied to a calculation of excitation functions and S factors for the system 16 O + 16 O, which has recently been investigated with various other theoretical approaches. It is suggested that this parametrization is useful for estimating sub-barrier fusion cross sections with exotic neutron-rich partners which cannot be studied in the laboratory.

Investigating energy dissipation through nucleon transfer reactions

“…The ground state is seen to be very weakly populated in the products of these reactions, with excited states populated up to tens of MeV even at energies far below the Coulomb barrier. These results support the importance of including dissipative couplings generated by cluster transfer in fusion models, which may prove important to describing the fusion hindrance effects [4,9] that are seen at low energies.…”

“…An abundance of recent measurements has shown this hindrance effect to be present in a wide variety of systems [5][6][7][8], such that it appears to be a general feature of heavy ion fusion. Importantly, this may affect fusion reactions of astrophysical importance [9,10], suggesting important consequences for stellar evolution. The physical origin of this phenomenon has been extensively sought [11][12][13], but no convincing explanation capable of consistently describing fusion above and below the Coulomb barrier has been forthcoming.…”

The effect of the nuclear state equation on the surface diffuseness parameter of the Woods–Saxon potential in the heavy ion fusion reactions

“…The main reason that does allow one to add an additional repulsive force to the NN interaction is the Pauli exclusion principle which does not permit the total density in the overlap region to exceed the saturated density. Recently it has been shown that this modification explains the steep-fall off effect in the interaction of the heavy ions [13][14][15][16][17][18][19][20]. As this repulsive term affects the internal and external parts of the nuclear potential in places where the fusion reaction is sensitive to them (see Fig.…”

THE STUDY OF THE NUCLEUS–NUCLEUS INTERACTION POTENTIAL FOR 16O+27Al AND 16O+28Si FUSION REACTIONS

“…1,2 Further research indicated that these changes can be attributed to the hindrance effects in fusion reactions. 3 In theoretical models which are based on the sudden approximation to calculate the nuclear potential, one can explain the observed changes in slope of the FeF by using the simulation of repulsive core effects. In fact these modifications take into account the effects of Pauli Exclusion Principle in calculation of nuclear potential and correct it in the inner regions.…”