Nuclear structure and decay modes of Ra isotopes within an axially deformed relativistic mean field model**Supported by Project No. SR/FTP/PS-106/2013, SERB, DST, Govt. of India

Abstract

We examine the structural properties and half-life decay of Ra isotopes within the axially deformed Relativistic Mean-Field (RMF) theory with NL3 force parameters. We work out the binding energy (BE), RMS radii, two-neutron separation energies (S2n), and some other observables. The results are in good agreement with the finite-range droplet model (FRDM) and experimental results. Considering the possibility of neutron magic number, the α-decay and cluster decay half-lives of Ra isotopes are calculated systematically using the Q-values obtained from the RMF formalism. These decay half-life calculations are carried out by taking three different empirical formulae. The calculated decay half-lives are found to be highly sensitive to the choice of Q-values. Possible shell or sub-shell closures are found at daughter nuclei with N = 128 and N = 126 when alpha and 8Be, 12C, 18O respectively are emitted from Ra isotopes. Though the cluster radioactivity is affected by the shell closure of parent and daughter, a long half-life indicates the stability of the parent, and a small parent half-life indicates that the shell stability of the daughter against decay.