Structural and alpha decay properties of even–even Polonium isotopes using relativistic mean-field approach

Abstract A comprehensive study is carried out, entailing the internal configuration of the ground state and the decay properties of the rarely abundant even–even Polonium isotopes within the mass range 186≤ A ≤218. A critical inspection of the density distribution of each of these nuclei reveals α -decay as their most probable decay mode. Thus, we have investigated the structural and decay properties using the relativistic mean-field (RMF) formalism with the NL3 * and relativistic-Hartree-Bogoliubov (RHB) with the DD-ME2 parameter set. The interaction barrier between the decay fragments is obtained by folding the RMF densities with the relativistic R3Y NN potentials. A relative comparison is included in calculation of the phenomenological potential of M3Y. The decay half-lives are estimated using the preformed cluster-decay model (PCM), where it is assumed that the emitted α -particle is preformed inside the parent nucleus and undergoes the quantum tunnelling process. The results are compared with the deformed relativistic Hartree-Bogoliubov theory in the continuum (DRHBc) with the PC-PK1 parameter set, the macroscopic-microscopic finite-range liquid droplet model (FRDM) and the available experimental data. It is apparent from structural analysis that there is a shape transition from oblate to prolate as the polonium isotopes are moved from neutron-deficient to neutron-rich isotopes. The entire decay mechanism is found to be governed by the proximity of their respective daughter nuclei to the closing of the magic neutron shell N = 126. We have also graphically shown the indispensable nature of penetrability P as the main contributor to the kinematically governed decay process via our newly proposed preformation formula and various break-up components of the Q-value. The study highlights the crucial need to refine the theoretical approaches employed, particularly relativistic-based frameworks and parameter sets, to accurately describe ground-state properties in this region for future experimental synthesis.