Dynamical cluster-decay model using various formulations of a proximity potential for compact non-coplanar nuclei: Application to the 64Ni+100Mo reaction

The dynamical cluster-decay model (DCM), using the well-known pocket formula of Blocki et al. [Ann. Phys. (NY) 105, 427 (1977)] for nuclear proximity potential, is extended to the use of various other nuclear proximity potentials with effects of deformations included up to hexadecapole (beta(4)) and compact orientations taken for both coplanar (Phi = 0) and non-coplanar (Phi not equal 0) configurations of nuclei for the first time. The other nuclear proximity potentials used are those derived from the Skyrme-energy-density-formalism-based semiclassical extended Thomas Fermi method under frozen density approximation for a compound nucleus, using SIII and GSkI Skyrme forces. This is in addition to extending the Blocki et al. interaction to compact and non-coplanar nuclei. Application of the method is made to the study of the decay of the hot and rotating compound nucleus Yb-164*, formed in the heavy-ion reaction Ni-64 + Mo-100 at both below- and above-barrier energies. For the best fitted measured evaporation residue cross-sections, consisting of x neutrons (x = 1-4), the interesting result of including the Phi degree of freedom is to increase the neck-length parameter of the model which results in the decrease of reaction time as well as the barrier-lowering parameter responsible for fusion hindrance effect. In other words, the fusion hindrance effect, a built-in property of DCM, though different for different nuclear interactions, reduces for the non-coplanar nuclei, and this reduction is more at higher center-of-mass energies. In the case of fusion-fission, only the CASCADE cross sections are available, which, when fitted simultaneously to another neck-length parameter, result in different components of a fusion-fission cross section for different nuclear interactions, including also the possibility of quasifission at the highest energy and the symmetric fission alone, that is, no intermediate-mass fragments, etc. The non-coplanar degree of freedom also plays an important role in changing the constituents of the fusion-fission cross section significantly, say, from intermediate and heavy-mass fragments plus the symmetric fission to simply the intermediate-mass fragments plus near-symmetric fission. This situation calls for the data for fusion-fission cross sections.