Possible origin of transition from symmetric to asymmetric fission

Physical origin of the transition from symmetric to asymmetric fission fragment charge distribution

“…The liquid-drop behavior of the system is also reflected in the quick increase of the driving potential when the charge (mass) number deviates from Z CN /2 (A CN /2). This is the physics origin of the central peak in the charge distribution [7].…”

“…We refer to the case of fissioning nucleus 224 MeV than for the symmetric division, the large number of mass fragmentations and the large width of the potential minima in the deformation plane (β L ,β H ) promote large yields in this charge region. The strong shell effects are also expressed in relatively small deformations of the corresponding nuclei [7]. For the nuclei with mass numbers larger than A L = 104, the shell effects are almost negligible, as Z L (N L ) are midway between proton (neutron) numbers of the closed shells.…”

“…In all cases, the three-peaked charge distribution is obtained at low excitation energy. One can also explain the origin of the triple-peaked charge distributions by examining the driving potentials [7]. We refer to the case of fissioning nucleus 224 MeV than for the symmetric division, the large number of mass fragmentations and the large width of the potential minima in the deformation plane (β L ,β H ) promote large yields in this charge region.…”

Role of the excitation energy of the compound nucleus in binary decay processes

“…Our aim is to explain the transformation of the charge distribution with neutron number in the electro-magneticinduced fission (E γ = 11 MeV) of Th isotopes and to predict the charge distributions at large excitation energies. The fission is described within the improved scission-point model [4]. The most important ingredient of the model is the potential energy of system as a function of charge (mass) asymmetry, deformations of the fission fragments, and internuclear distance.…”

“…The knowledge of the deformations of nascent fragments at scission point is also crucial. consists of the Coulomb interaction potential V C of the two uniformly charged ellipsoids and nuclear interaction potential V N in the double-folding form [4]. The interaction potential presents an inner potential pocket and external barrier which prevents the system from decay.…”