Exploring the fusion hindrance phenomenon: the case of ^32,34S + ⁸⁹Y

Abstract

The sub-barrier fusion data of 32,34S + 89Y colliding systems are analyzed using the coupled-channels (CC) calculations, including couplings to the low-lying 2+ and 3− states in reacting nuclei as well as mutual and multi-phonon excitations of these states, based on the proximity potential model. In this scheme, we focus upon the the effect of surface energy coefficient γ and also thermal properties of liquids and hot nuclei on the inner part of the nuclear potential and thus on the fusion cross sections at bombarding energies far below the Coulomb barrier. As expected, our primary calculations using the original proximity potential 1977 show that this model underestimates the measured fusion cross sections at the whole energy region. It is shown that the mentioned physical effects bring significant cross sections enhancements for both reactions. The indications of the fusion hindrance phenomenon in the fusion cross sections at energies far below the Coulomb barrier show up. The observed S factors for the above-mentioned systems develop a maximum at low energies which can also be predicted by the phenomenological extrapolations. Our results within the framework of the modified form of the proximity potential reveal that the calculated fusion cross sections, S factors, and logarithmic slopes for the two systems are in good agreement with the corresponding experimental data even at the lowest energies.

Possibilities of synthesizing new proton-rich nuclei with 40 ≤ Z ≤ 60 using multinucleon transfer reactions *

“…This is primarily because, in addition to deep inelastic scattering and quasi-fission, fusion evaporation has an important role in the system Ni+ Te (compound nucleus Hg), whereas our theoretical model (DNS model) primarily considers the role of deep inelastic scattering and quasi-fission processes. However, for the Ni+ Pb [55],…”

Survey of deep sub-barrier heavy-ion fusion hindrance phenomenon for positive and negative Q-value systems using the proximity-type potential

“…In fact, we discuss the effect of the surface energy coefficient and the thermal effects of hot nuclei on the proximity potential and ulti-mately on the fusion cross sections of the considered systems. According to the literature [26,27,39], the mentioned physical effects play a crucial role in the sub-barrier enhancement. To implement this idea, it is crucial to use a modified version of the surface energy coefficient in the proximity potential as follows,…”

“…Recently, we proposed a dynamical approach to evaluate the heavy-ion fusion cross sections at deep sub-barrier energies within the framework of the energy-dependent nucleus-nucleus potential [26]. It was shown that when the effect of the surface energy coefficients and the temperature-dependence in the original proximity potential 1977 are taken into account, the theoretical fusion cross sections calculated using the CC calculations provide a good description of the steep falloff phenomenon at low energies for the 28 Si+ 100 Mo, 58 Ni+ 54 Fe, and 64 Ni+ 64 Ni systems.…”

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

“…The fusing process between two nuclei is extremely important on theoretical as well as experimental grounds because it is related with the involvement of inherent channels that arise because of structure of colliding nuclei during reaction dynamics [1,2]. For a larger number of heavy-ion events, experimental data at below Coulomb barrier energies are found to be too much larger over outcomes of simple barrier penetration model (BPM) and such difference between theoretical and experimental results is termed as "fusion enhancement" [1,2]. In simple BPM, the internal structure of fusing nuclei is generally ignored and the theoretical estimations are done by considering the relative motion co-ordinate only.…”

“…In simple BPM, the internal structure of fusing nuclei is generally ignored and the theoretical estimations are done by considering the relative motion co-ordinate only. Numerous studies have been looked in past [1,2] for analyzing the importance of vibrational states and permanent shape deformations due to the structure of participants that might affect fusion cross-sections yields at energies lie below nominal barrier. Besides this, the function of surface rotational effects as well as the vibrational coupling effects of fusing nuclei are partially understood.…”