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Register a new userStructural and decay properties of $Z=132,138$ superheavy nuclei
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In this paper, we analyze the structural properties of $Z=132$ and $Z=138$ superheavy nuclei within the ambit of axially deformed relativistic mean-field framework with NL$3^{*}$ parametrization and calculate the total binding energies, radii, quadrupole deformation parameter, separation energies, density distributions. We also investigate the phenomenon of shape coexistence by performing the calculations for prolate, oblate and spherical configurations. For clear presentation of nucleon distributions, the two-dimensional contour representation of individual nucleon density and total matter density has been made. Further, a competition between possible decay modes such as $alpha$-decay, $beta$-decay and spontaneous fission of the isotopic chain of superheavy nuclei with $Z=132$ within the range 312 $le$ A $le$ 392 and 318 $le$ A $le$ 398 for $Z=138$ is systematically analyzed within self-consistent relativistic mean field model. From our analysis, we inferred that the $alpha$-decay and spontaneous fission are the principal modes of decay in majority of the isotopes of superheavy nuclei under investigation apart from $beta$ decay as dominant mode of decay in $^{318-322}138$ isotopes.
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In this manuscript, we analyze the structural properties of $Z=119$ superheavy nuclei in the mass range of 284 $le$ A $le$ 375 within the framework of deformed relativistic mean field theory (RMF) and calculate the binding energy, radii, quadrupole deformation parameter, separation energies and density profile. Further, a competition between possible decay modes such as $alpha-$decay, $beta-$decay and spontaneous fission (SF) of the isotopic chain of $Z=119$ superheavy nuclei under study is systematically analyzed within self-consistent relativistic mean field model. Moreover, our analysis confirmed that $alpha-$decay is restricted within the mass range 284 $leq$ A $leq$ 296 and thus being the dominant decay channel in this mass range. However, for the mass range 297 $leq$ A $leq$ 375 the nuclei are unable to survive fission and hence SF is the principal mode of decay for these isotopes. There is no possibility of $beta-$decay for the considered isotopic chain. In addition, we forecasted the mode of decay $^{284-296}$119 as one $alpha$ chain from $^{284}$119 and $^{296}$119, two consistent $alpha$ chains from $^{285}$119 and $^{295}$119, three consistent $alpha$ chains from $^{286}$119 and $^{294}$119, four consistent alpha chains from $^{287}$119, six consistent alpha chains from $^{288-293}$119. Also from our analysis we inferred that for the isotopes $^{264-266,269}$Bh both $alpha$ decay and SF are equally competent and can decay via either of these two modes. Thus, such studies can be of great significance to the experimentalists in very near future for synthesizing $Z=119$ superheavy nuclei.
Structural properties and the decay modes of the superheavy elements Z $=$ 122, 120, 118 are studied in a microscopic framework. We evaluate the binding energy, one- and two- proton and neutron separation energy, shell correction and density profile of even and odd isotopes of Z $=$ 122, 120, 118 (284 $leq$ A $leq$ 352) which show a reasonable match with FRDM results and the available experimental data. Equillibrium shape and deformation of the superheavy region are predicted. We investigate the possible decay modes of this region specifically $alpha$-decay, spontaneous fission (SF) and the $beta$-decay and evaluate the probable $alpha$-decay chains. The phenomena of bubble like structure in the charge density is predicted in $^{330}$122, $^{292,328}$120 and $^{326}$118 with significant depletion fraction around 20-24$%$ which increases with increasing Coulomb energy and diminishes with increasing isospin (N$-$Z) values exhibiting the fact that the coloumb forces are the main driving force in the central depletion in superheavy systems.
Transfermium nuclei (101$leq$Z$leq$110) are investigated thoroughly to describe structural properties viz. deformation, radii, shapes, magicity, etc. as well as their probable decay chains. These properties are explored using relativistic mean-field (RMF) approach and compared with other theories along with available experimental data. Neutron numbers N$=$152 and 162 have come forth with a deformed shell gap whereas N$=$184 is ensured as a spherical magic number. The region with N$>$168 bears witness of the phenomenon of shape transition and shape coexistence for all the considered isotopic chains. Experimental $alpha$-decay half-lives are compared with our theoretical half-lives obtained by using various empirical/semi-empirical formulas. The recent formula proposed by Manjunatha textit{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 $alpha$-decay chains that are found in excellent agreement with available experimental data.
A fully systematic study of even and odd isotopes (281 $leq$ A $leq$ 380) of Z = 121 superheavy nuclei is presented in theoretical frameworks of Relativistic mean-field plus state dependent BCS approach and Macroscopic-Microscopic approach with triaxially deformed Nilson Strutinsky prescription. The ground state properties namely shell correction, binding energy, two- and one- proton and neutron separation energy, shape, deformation, density profile and the radius are estimated that show strong evidence for magicity in N = 164, 228. Central depletion in the charge density due to large repulsive Coulomb field indicating bubble-like structure is reported. A comprehensive analysis of the possible decay modes specifically $alpha$-decay and spontaneous fission (SF) is presented and the probable $alpha$-decay chains are evaluated. Results are compared with FRDM calculations and the available experimental data which show excellent agreement.
A recent high-resolution $alpha$, $X$-ray, and $gamma$-ray coincidence-spectroscopy experiment offered first glimpse of excitation schemes of isotopes along $alpha$-decay chains of $Z=115$. To understand these observations and to make predictions about shell structure of superheavy nuclei below $^{288}115$, we employ two complementary mean-field models: self-consistent Skyrme Energy Density Functional approach and the macroscopic-microscopic Nilsson model. We discuss the spectroscopic information carried by the new data. In particular, candidates for the experimentally observed $E1$ transitions in $^{276}$Mt are proposed. We find that the presence and nature of low-energy $E1$ transitions in well-deformed nuclei around $Z=110, N=168$ strongly depends on the strength of the spin-orbit coupling; hence, it provides an excellent constraint on theoretical models of superheavy nuclei. To clarify competing theoretical scenarios, an experimental search for $E1$ transitions in odd-$A$ systems $^{275,277}$Mt, $^{275}$Hs, and $^{277}$Ds is strongly recommended.
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