Comprehensive analysis of heavy-ion fusion reactions around the Coulomb barrier

Abstract

We have investigated the fusion dynamics of 12C + 92Zr, 16O + 92Zr, 28Si + 92Zr, 35Cl + 92Zr, 16O + 60Ni, 18O + 58Ni, 12C + 194,198Pt, 16O + 144,148,154Sm and 17O + 144Sm reactions in the close vicinity of the Coulomb barrier. For this purpose, we have opted one-dimensional Wong formula, coupled channel approach, and symmetric-asymmetric Gaussian barrier distribution (SAGBD) model to analyze the fusion data for above mentioned reactions. For all studied systems, the theoretical results obtained from the one-dimensional Wong formula are unable to reproduce the fusion data especially at incident energies lying below the nominal barrier. This appeals for the inclusion of intrinsic degrees of freedom which have been originated from the nuclear structure of fusing nuclei, and thus essentially required to explain the experimental data at energies lying in the sub-barrier realm. For the chosen reactions, the coupled channel analysis suggests that the coupling of relative motion with the inelastic surface excitations and/or nucleon transfer channels associated with the reaction partners have produced a remarkable fusion enhancement at energies lying near and below the nominal barrier. It is particularly intriguing that the SAGBD model can replicate the impacts of dominant intrinsic reaction channels such as multi-phonon quantum states and/or nucleon transfer channels via Gaussian type of weight function. The predictions of the SAGBD approach appropriately reproduce the fusion cross-sections data and related barrier distributions data for the selected reactions due the fact that the multi-dimensional nature induces the barrier lowering effects and subsequently reduces the effective fusion barrier between the participants. In the SAGBD approach, the channel coupling effects are quantitively measured in terms of channel coupling parameter (λ) and percentage decrement in height of effective fusion barrier with respect to the Coulomb barrier (VCBRED ) . Furthermore, the recovered x 2-values for selected reactions are found to be smaller and hence clearly demonstrate the applicability of the model outcomes to explore the fusion dynamics of the studied systems.

Fusion of 16O + 60Ni and 18O + 58Ni reactions

“…Despite of the fact that both events have different entrance channels, yet produce same composite nucleus i.e., 76 Kr. According to the published literature [3], higher mass asymmetry (η) increases possibility to happen fusion in sub-barrier realm. The values of η for 16 O + 60 Ni and 18 O + 58 Ni reactions are 0.579 and 0.526, respectively [3].…”

“…According to the published literature [3], higher mass asymmetry (η) increases possibility to happen fusion in sub-barrier realm. The values of η for 16 O + 60 Ni and 18 O + 58 Ni reactions are 0.579 and 0.526, respectively [3]. Besides smaller value of η, 18 O + 58 Ni reaction exhibits greater fusion enhancement that can be connected with PQNT channel.…”

“…The connection of interacting partners' internal channels with their relative motion effectively modifies tunnelling process & yields higher fusion crosssections than results due to simple BPM in lower energy realm [1]. In present work, the fusion data for 16 O + 60 Ni and 18 O + 58 Ni reactions are theoretically analyzed within the preview of Wong formula [2] & SAGBD method [3]. The Wong based estimations fail drastically to retrieve experimental data while SAGBD model addresses fusion data of 16 O + 60 Ni and 18 O + 58 Ni systems [4].…”

“…mean barrier height & standard deviation of barrier distribution. For more deep insight of SAGBD formalism, one can read Ref [3]…”

Fusion of Stable Odd-A isotope targets with Doubly Magic 16O Projectile

“…Current work analyzes the fusion dynamics of stable odd-A targets 147,149 Sm with 16 O projectile in sub-barrier domain by using simple Wong formula [3] and SAGBD formalism [4]. Results due to Wong formula fails to replicate fusion data for both systems in sub-barrier domain, whereas above barrier data are explained by using such model.…”