No abstract

Transfermium nuclei (101≤Z≤110) are investigated thoroughly to describe structural properties viz. deformation, radii, shapes, magicity, etc. as well as their probable decay chains. These properties are explored using relativistic mean-field (RMF) approach and compared with other theories along with available experimental data. Neutron numbers N=152 and 162 have come forth with a deformed shell gap whereas N=184 is ensured as a spherical magic number. The region with N>168 bears witness of the phenomenon of shape transition and shape coexistence for all the considered isotopic chains. Experimental α-decay half-lives are compared with our theoretical halflives obtained by using various empirical/semi-empirical formulas. The recent formula proposed by Manjunatha et al., which results best among the considered 10 formulas, is further modified by adding asymmetry dependent terms (I and I 2). This modified Manjunatha formula is utilized to predict probable α-decay chains that are found in excellent agreement with available experimental data.

The exotic phenomenon of two-neutron halos and 2n-radioactivity are explored in the neutron-rich 40,42,44Mg by employing various variants of the relativistic mean-field approach. The extended tail of spatial density distributions including the enhanced neutron radii and skin thickness, pairing correlations, single-particle spectrum and wave functions predict 40,42,44Mg to be strong candidates for deformed neutron halos. Weakening of magicity at N = 28 plays a significant role in the existence of a weakly bound halo in 40Mg which is currently the heaviest isotope of Mg accessible experimentally. Large deformation, mixing of f–p shell Nilsson orbitals and the valence neutron occupancy of p-states leads to a reduced centrifugal barrier and broader spatial density distributions that favour 2n-radioactivity in 42,44Mg.

In this paper, various ground state properties are explored for full isotonic(isotopic) chain of neutron number N [Formula: see text]proton number [Formula: see text] using different families of Relativistic Mean-Field theory. Several properties, such as nucleon separation energies, pairing energies, deformation, radii and nucleon density distributions, are evaluated and compared with the experimental data as well as those from other microscopic and macroscopic models. [Formula: see text] isotonic chain presents ample of support for the neutron magicity and articulates double magicity in recently discovered [Formula: see text]Ca and [Formula: see text]Ni. Our results are in close conformity with the recently measured value of charge radius of [Formula: see text]Ni [S. Kaufmann et al., Phys. Rev. Lett. 124 (2020) 132502] which supports the [Formula: see text] magicity. Contrarily, Zr isotopes ([Formula: see text]) display variety of shapes leading to the phenomenon of shape transitions and shape co-existence. The role of 3s[Formula: see text] state, which leads to central depletion if unoccupied, is also investigated. [Formula: see text]S and [Formula: see text]Zr are found to be doubly bubble nuclei.

Cluster radioactivity is one of the exotic phenomena which offers an alternate emission in heavy and superheavy nuclei in addition to the α-decay and spontaneous fission. In the present work, we predict half-lives of cluster decay in superheavy nuclei 294,296 Og by picking up the emission of all possible even-even isotopes from He to Mo (Z=2-42). These half-lives are compared with the half-lives of α-decay, and accordingly the possibility of most probable cluster emission is ascertained. For these decay processes, the disintegration energies (Q-values) are taken from WS4 mass model. To estimate cluster emission half-lives, we use few widely known empirical formulas i.e. Horoi [