247 research outputs found
Relativistic Energy Density Functional Description of Shape Transition in Superheavy Nuclei
Relativistic energy density functionals (REDF) provide a complete and
accurate, global description of nuclear structure phenomena. A modern
semi-empirical functional, adjusted to the nuclear matter equation of state and
to empirical masses of deformed nuclei, is applied to studies of shapes of
superheavy nuclei. The theoretical framework is tested in a comparison of
calculated masses, quadrupole deformations, and potential energy barriers to
available data on actinide isotopes. Self-consistent mean-field calculations
predict a variety of spherical, axial and triaxial shapes of long-lived
superheavy nuclei, and their alpha-decay energies and half-lives are compared
to data. A microscopic, REDF-based, quadrupole collective Hamiltonian model is
used to study the effect of explicit treatment of collective correlations in
the calculation of Q{\alpha} values and half-lives.Comment: 23 pages, 10 figure
Relativistic mean field study of the properties of Z=117 nucleus and the decay chains of 117 isotopes
We have calculated the binding energy, root-mean-square radius and quadrupole
deformation parameter for the recently synthesized superheavy element Z=117,
using the axially deformed relativistic mean field (RMF) model. The calculation
is extended to various isotopes of Z=117 element, strarting from A=286 till
A=310. We predict almost spherical structures in the ground state for almost
all the isotopes. A shape transition appears at about A=292 from prolate to a
oblate shape structures of Z=117 nucleus in our mean field approach. The most
stable isotope (largest binding energy per nucleon) is found to be the
117 nucleus. Also, the Q-value of -decay and the
half-lives are calculated for the -decay chains of
117 and 117, supporting the magic numbers at N=172 and/ or 184.Comment: 6 Pages and 8 Figure
Alpha decay chains study for the recently observed superheavy element Z=117 within the Isospin Cluster Model
The recently observed -decay chains were produced by
the fusion reactions with target and projectile at Dubna
in Russia. The reported cross-sections for the mentioned reaction are
pb and =1.3(+1.5,-0.6) at and
, respectively. The Q-values of -decay and the half-lives
(s) are calculated for the -decay chains of
nuclei, within the framework of Isospin Cluster Model (ICM). In
the ICM model the proximity energy is improved by using the isospin dependent
radius of parent, daughter and alpha particle. The binding energy (i=1,2) of any nucleus of mass number A and atomic number Z was
obtained from a phenomenological and more genaralized BW formula given by
\cite{samanta02}. The calculated results in ICM are compared with the
experimental results and other theoretical Macro-Microscopic(M-M), RMF(with NL3
and SFU Gold forces parameter) model calculations. The estimated values of
-decay half-lives are in good agreement with the recent data. The ICM
calculation is in favor of the persence of magic number at N=172
Analytical relationship for the cranking inertia
The wave function of a spheroidal harmonic oscillator without spin-orbit
interaction is expressed in terms of associated Laguerre and Hermite
polynomials. The pairing gap and Fermi energy are found by solving the BCS
system of two equations. Analytical relationships for the matrix elements of
inertia are obtained function of the main quantum numbers and potential
derivative. They may be used to test complex computer codes one should develop
in a realistic approach of the fission dynamics. The results given for the
Pu nucleus are compared with a hydrodynamical model. The importance of
taking into account the correction term due to the variation of the occupation
number is stressed.Comment: 12 pages, 4 figure
A Particle number conserving shell-correction method
The shell correction method is revisited. Contrary to the traditional
Strutinsky method, the shell energy is evaluated by an averaging over the
number of particles and not over the single-particle energies, which is more
consistent with the definition of the macroscopic energy. In addition, the
smooth background is subtracted before averaging the sum of single-particle
energies, which significantly improves the plateau condition and allows to
apply the method also for nuclei close to the proton or neutron drip lines. A
significant difference between the shell correction energy obtained with the
traditional and the new method is found in particular for highly degenerated
single-particle spectra (as i.e. in magic nuclei) while for deformed nuclei
(where the degeneracy is lifted to a large extent) both estimates are close,
except in the region of super or hyper-deformed states.Comment: 11 pages in LaTeX, 7 figure
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