Static and dynamic fusion barriers in heavy-ion reactions

Abstract. We discuss a simple symmetry-adapted method for the determination of the shape isomers, and for the study of their possible fragmentation. In other words the connection between the quadrupole (collective) and dipole (cluster) degrees of freedom is considered in terms of an easily applicable, yet microscopic method. The energetics is taken into account by the double-folding method. Special attention is focused on those cases in which the theoretical predictions have a direct comparison with experimental observation.

Section: Nimentioning

confidence: 99%

Extreme quadrupole deformation and clusterization

Darai

Cseh

Adamian

et al. 2012

“…3). More generally, it has been proved that the potential barrier heights in this valley correspond precisely to the fission barrier heights [5][6][7][8][9].…”

Section: Potential Barriersmentioning

confidence: 84%

“…Within a Generalized Liquid Drop Model (GLDM) taking into account the mass and charge asymmetries, the proximity energy, and the shell and pairing energies, it has been demonstrated that there is a degeneracy between the energy of quasimolecular shapes and the energy of elongated shapes with a shallow neck. Most of the binary and ternary fission, and light nucleus emission and fusion properties have been also reproduced in this quasimolecular shape valley [5][6][7][8][9]. The purpose of this work is to investigate the actinide region remaining in this a e-mail: royer@subatech.in2p3.fr This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.…”

Section: Introductionmentioning

confidence: 83%

Fission of actinides through quasimolecular shapes

Royer¹,

Zhang

Eudes³

et al. 2013

Abstract. The potential energy of heavy nuclei has been calculated in the quasimolecular shape path from a generalized liquid drop model including the proximity energy, the charge and mass asymmetries and the microscopic corrections. The potential barriers are multiplehumped. The second maximum is the saddle-point. It corresponds to the transition from compact one-body shapes with a deep neck to two touching ellipsoids. The scission point lies at the end of an energy plateau well below the saddle-point and where the effects of the nuclear attractive forces between two separated fragments vanish. The energy on this plateau is the sum of the kinetic and excitation energies of the fragments. The shell and pairing corrections play an essential role to select the most probable fission path. The potential barrier heights agree with the experimental data and the theoretical half-lives follow the trend of the experimental values. A third peak and a shallow third minimum appear in asymmetric decay paths when one fragment is close to a double magic quasispherical nucleus, while the smaller one changes from oblate to prolate shapes.

“…It is suggested that the transition from the contact configuration to the CN configuration is determined by a presence of the conditional barrier along the mass-asymmetry coordinate [13] and the entrance-point position with respect to the top of the barrier, i.e., relatively to the Businaro-Gallone (BG) point [14]. The Generalized Liquid-Drop Model (GLDM) [15] calculations of the potential energy surface (PES) in the (Z, N)-plane for the contact configuration of spherical nuclei give us an examination of the PES for the 216 Ra * CN in more detail (see Figure 1) than considered in [11]. The calculations take into account proximity energy [16].…”

Section: Introductionmentioning

confidence: 99%

“…1. Driving potential extracted from the PES obtained in the framework of GLDM [15,16] for the 216 Ra CN as a function of the mass asymmetry (solid and dashed lines corresponding to the calculations with and without shell corrections [17], respectively). Filled and open circles correspond to the positions of the entrance points on PES for some combinations, which are also calculated with and without shell corrections [17], respectively.…”

Section: Introductionmentioning

confidence: 99%

Fusion probability and survivability in estimates of heaviest nuclei production

Sagaidak

2012

Abstract. Production of the heavy and heaviest nuclei (from Po to the region of superheavy elements close to Z=114 and N=184) in fusion-evaporation reactions induced by heavy ions has been considered in a systematic way within the framework of the barrier-passing model coupled with the statistical model (SM) of de-excitation of a compound nucleus (CN). Excitation functions for fission and evaporation residues (ER) measured in very asymmetric combinations can be described rather well. One can scale and fix macroscopic (liquid-drop) fission barriers for nuclei involved in the calculation of survivability with SM. In less asymmetric combinations, effects of fusion suppression caused by quasi-fission (QF) are starting to appear in the entrance channel of reactions. QF effects could be semi-empirically taken into account using fusion probabilities deduced as the ratio of measured ER cross sections to the ones obtained in the assumption of absence of the fusion suppression in corresponding reactions. SM parameters (fission barriers) obtained at the analysis of a very asymmetric combination leading to the production of (nearly) the same CN should be used for this evaluation.