Abstract
The decay mechanism of compound nucleus (CN) , formed in reaction, is studied within the dynamical cluster-decay model (DCM) at various excitation energies , where neutron emission , , are the predominant decay modes. The study is of interest since decays to the ground state (g.s.) of by emission of and to metastable states and via () emission, respectively. The DCM is applied here for the first time to the decays of metastable states. Both types of decays are analyzed separately, using neck-length (equivalently, barrier-lowering) parameter, the only parameter in the DCM, to best fit the evaporation residue or channel cross section () data and predict the quasifissionlike (qf-like) noncompound () and fusion-fission () cross sections. For g.s. to g.s. decay of , possibly due to involving the deformed rare-earth lanthanide target , the observed decay channel requires the noncompound nucleus (nCN) contribution, treated as the qf-like process. On the other hand, the decay mechanism of to metastable states (m.s.) and , is a pure CN decay, i.e., the is zero. In this study, we have included the deformation effects up to quadrupole deformations and optimum orientations for coplanar () nuclei, using hot-compact configurations, supporting asymmetric fission of CN . The variation of CN formation probability and survival probability with excitation energy is in complete agreement with the known systematic of other radioactive CN studied so far, thereby giving credence to the predicted in g.s. to g.s. decay and fusion-fission cross section of . Interestingly, both the observed g.s. to g.s. and g.s. to m.s. processes occur at a fixed , which is within the nuclear proximity limit of , and hence useful for making predictions.
2 More- Received 3 May 2018
DOI:https://doi.org/10.1103/PhysRevC.98.014602
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