Unraveling the Decay Dynamics of Heavy-Ion Induced Reactions Forming Lanthanide Nuclei at Low-Energy Regime

The investigation of various decay mechanisms, including evaporation residue (ER), intermediate mass fragments (IMF), heavy mass fragments (HMF), and fission fragments, has predominantly been observed to contribute at varying proportions. The observation has sparked our curiosity to delve deeper into the decay dynamics of few compound nuclei. Following compound nuclei from the lanthanide series, i.e., \(^{\varvec{131}}\)La\(^{\varvec{*}}\), \(^{\varvec{143}}\)Pr\(^{\varvec{*}}\), \(^{\varvec{144}}\)Nd\(^{\varvec{*}}\), \(^{\varvec{146}}\)Sm\(^{\varvec{*}}\), \(^{\varvec{148,150}}\)Gd\(^{\varvec{*}}\), \(^{\varvec{149}}\)Eu\(^{\varvec{*}}\), \(^{\varvec{151,153}}\)Tb\(^{\varvec{*}}\), \(^{\varvec{152,158}}\)Dy\(^{\varvec{*}}\), \(^{\varvec{156,158,160,162,164,166}}\)Er\(^{\varvec{*}}\), \(^{\varvec{157}}\)Ho\(^{\varvec{*}}\), \(^{\varvec{161}}\)Tm\(^{\varvec{*}}\), \(^{\varvec{162,164,166,168}}\)Yb\(^{\varvec{*}}\) are chosen. We have used the Dynamical Cluster-decay Model (DCM), rooted in the Quantum Mechanical Fragmentation Theory (QMFT). This model offers a balanced treatment of various decay mechanisms, facilitating comprehension of compound nuclear dynamics. The calculated ER cross-sections, incorporating quadrupole \({\varvec{\beta }}_{\varvec{2}}\) deformation and optimal orientations, find decent agreement with the experimental data. The elongated orientation seems appropriate at below-barrier energies and the compact orientations at above-barrier energies. The fragmentation structure of compound nuclei reveals distinct decay fragments across mass regions (IMF, HMF, and fission fragments), emphasizing the role of nuclear magicity and deformation effects. A shift from broad shoulder structure to triple-humped mass distribution occurs as one proceeds from lower mass lanthanide to heavy mass lanthanide emphasizing the relative competition among decay fragments. Our study elucidates the fragmentation characteristics of lanthanide nuclei formed via heavy-ion-induced reactions, revealing the distinct preference of fragments in the decay process. Notably, deformations and orientation effects impart a discernible influence on the mass distribution. Proton and neutron magicity is evident in the analysis.