Dynamics of Ca40,48+238U→278,286112⁎ reactions across the Coulomb barrier using dynamical cluster decay model

The role of deformations and related orientations (optimum or compact) is investigated in reference to dynamics of Ca40,48+238U→278,286112⁎ reactions using dynamical cluster decay model (DCM). The use of quadrupole and hexadecapole deformations in the decay of compound system suggest that the degree of compactness changes with addition of higher order deformations. The decay cross-sections are calculated in reference to the available data, including β2-static deformations within 'optimum' orientation approach. The comparative analysis of spherical, β2-static and dynamic alongwith β4-static deformations is investigated at comparable center of mass energy of 230 MeV for both nuclei. To address the specific role of optimized orientations in the decay of 112⁎278 and 112⁎286 nuclei, the calculations are done using equatorial compact and polar elongated orientations. Using hot equatorial collisions, symmetric fission is observed as the dominant decay mode across the barrier, which otherwise becomes asymmetric for cold elongated approach. The calculated cross-sections match nicely with experimental data using hot configuration but the same are overestimated for the use of cold (polar) orientation approach at deep sub-barrier region. This overestimation in the deep sub-barrier region may be associated with the quasi-fission decay channel. The contribution of QF in both 112⁎278 and 112⁎286 nuclei are predicted through the overestimated cross-sections being more for neutron-deficient 112⁎278 nucleus, in agreement with experimental results. Larger barrier modification ΔVB is observed at sub-barrier energies for both isotopes of Z=112 nucleus. Also the contribution of ΔVB at lower incident energies is relatively higher for cold elongated polar configuration as compared to hot compact equatorial configuration, causing overestimation of cross-section for the use of cold approach.