We study nuclear structure properties for various isotopes of Ytterbium (Yb), Hafnium(Hf), Tungsten(W), Osmium(Os), Platinum(Pt) and Mercury(Hg) in Z = 70 − 80 drip-line region starting from N = 80 to N = 170 within the formalism of relativistic mean field (RMF) theory. The pairing correlation is taken care by using BCS approach. We compared our results with Finite Range Droplet Model(FRDM) and experimental data and found that the calculated results are in good agreement. Neutron shell closure are obtained at N = 82 and 126 in this region. We have also studied probable decay mechanisms of these elements.

We study the extremely neutron-rich nuclei for Z = 17 − 23, 37 − 40 and 60 − 64 regions of the periodic table by using axially deformed relativistic mean field formalism with NL3* parametrization. Based on the analysis of binding energy, two neutron separation energy, quadrupole deformation and root mean square radii, we emphasized the speciality of these considered regions which are recently predicted islands of inversion.

We study the bulk properties such as binding energy (BE), root-mean-square (RMS) charge radius, quadrupole deformation etc. for Francium (F r) isotopes having mass number A = 180-240 within the framework of relativistic mean field (RMF) theory. Systematic comparisons are made between the calculated results from RMF theory, Finite Range Droplet Model (FRDM) and the experimental data. Most of the nuclei in the isotopic chain shows prolate configuration in their ground state. The α-decay properties like αdecay energy and the decay half-life are also estimated for three different chains of 198 Fr, 199 Fr and 200 Fr. The calculation for the decay half-life are carried out by taking two different empirical formulae and the results are compared with the experimental data. Int. J. Mod. Phys. E 2015.24. Downloaded from www.worldscientific.com by UNIVERSITY OF QUEENSLAND on 10/06/15. For personal use only. M. Bhuyan et al.information regarding the synthesis of new element due to stellar evolution. 5-7 Further, the elements in this region, such as Francium (Fr ) or Astatine, are very rarely abundant on the earth and they are only observed in nature by the decay chains of heavy elements. The structure of these neutron-deficient nuclei has attracted a lot of interest due to a multitude of phenomena because of the vicinity to the closed proton shell at Z = 82. A systematic appearance of low-lying intruder state is also one of the most amusing phenomena of this region. 1,8,9 Again, the studies of the Odd-Odd nuclei are difficult because of the coupling of odd valence nucleon results in multiple states, both normal and intruder, some members of which can become isomeric. 10 Hence, the α-decay often allows an ideal tool to identify their states in the daughter nucleus which has identical spin, parity as the parent nucleus. 11,12 In addition to that, the α-decay also plays a crucial role to investigate the exotic nuclei at drip-line and superheavy region. [13][14][15][16] Recently, the synthesis of neutron-deficient 198,199,200 F r from heavy-ion induced fusion-evaporation reactions of the type 141 Pr + 60 Ni → 201−x Fr, which decay simultaneously via "x" number of neutrons, 17 motivates us to focus on their structural as well as decay properties, using a microscopic theoretical model with well established force parameter. The objective of this paper is an investigation of the structure and the decay properties of F r isotopes in the framework of relativistic mean field (RMF) theory, since the time when the idea of deformed isotopes has appeared. This idea stimulated very much the studies, both theoretical and experimental, as the region of drip-line heavy nuclei is expected to be much closer to already known nuclei than the region of spherical one and, thus, much easier to be reached in experiment. More elaborately, the present investigation of F r isotopes far from the β-stable region is also a demanding field in nuclear structure physics. It provides some information towards the understanding of "Magicity" near drip-line regi...

We study the binding energy, root-mean-square radius and quadrupole deformation parameter for the synthesized superheavy element Z = 115, within the formalism of relativistic mean field theory. The calculation is dones for various isotopes of Z = 115 element, starting from A = 272 to A = 292. A systematic comparison between the binding energies and experimental data is made.The calculated binding energies are in good agreement with experimental result. The results show the prolate deformation for the ground state of these nuclei. The most stable isotope is found to be 282 115 nucleus (N = 167) in the isotopic chain. We have also studied Qα and Tα for the α-decay chains of 287,288 115. Keywords: Nuclear structure; relativistic mean field theory; nuclear density; α-decay half-live. 2217 Int. J. Mod. Phys. E 2011.20:2217-2228. Downloaded from www.worldscientific.com by UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL on 02/03/15. For personal use only. 2218 B. K. Sahu et al.spherical doubly magic nucleus heavier than 208 Pb arises in every advanced model of nuclear structure. 1 The elements up to Z = 118 have been synthesized till today with half-lives varying from a few minutes to milliseconds. 1,2 But theoretically predicted center of the island of stability could not be located. More microscopic theoretical calculations have predicted various regions of stability, namely Z = 120, N = 172 or 184 (see Refs. 3-5) and Z = 124 or 126, N = 184 (see .There is a need to design the new experiments to solve the outstanding problem of locating the precise island of stability for SHE. Measurements on the α-decays provide reliable information on nuclear structure such as ground state energies, half-lives, nuclear spins and parities, shell effects, nuclear deformation and shape co-existence. 9-17 Therefore as one of the most important decay channels for unstable nuclei, α-decay is extensively investigated both experimentally and theoretically.Both non-relativistic (e.g. Skyrme-Hartree-Fock) theory 18,19 and relativistic microscopic mean field formalism (RMF) 20,21 predict probable shell closures at Z = 114 and 120. Microscopic interaction for the existence of the heaviest element was estimated by Meitner and Frisch. 22 Myers and Swiatecki 23 estimated the fission barriers for wide range of nuclei and also far into the unknown region of SHE. The historical review on theoretical predictions and new experimental possibilities are given by Sobiczewski, Garrev and Kalinkin. 24 A considerable increase in nuclear stability was expected for the heaviest nuclei with N > 170 in the vicinity of the closed spherical shells, Z = 114 ( or possibly 120, 122 or 126) and N = 184, similar to the effect of the closed shells on the stability of the doubly magic 208 Pb (Z = 82, N = 126) (see . The change of shape from spherical to deformed (oblate/prolate) configuration in the α-decay process gives us valuable information about the nuclear structure properties. [25][26][27][28][29] The fusion-evaporation reaction of 243 Am + 48 Ca, leads to the forma...