Shell Model Calculations for Nuclei with A=20 (original) (raw)
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Nuclear binding energies: Global collective structure and local shell-model correlations
Nuclear Physics A, 2002
Nuclear binding energies and two-neutron separation energies are analysed starting from the liquid-drop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently concentrate on the Interacting Boson Model (IBM) and discuss a new method in order to provide a consistent description of both, ground-state and excitedstate properties. We address the artefacts that appear when crossing midshell using the IBM formulation and perform detailed numerical calculations for nuclei situated in the 50−82 shell. We also concentrate on local deviations from the above global trends in binding energy and two-neutron separation energies that appear in the neutron-deficient Pb region. We address possible effects on the binding energy, caused by mixing of low-lying 0 + intruder states into the ground state, using configuration mixing in the IBM framework. We also study ground-state properties using a macroscopic-microscopic * Postdoctoral fellow of the Fund for Scientific Research-Flanders (Belgium). † Visiting postdoctoral fellow of the Fund for Scientific Research-Flanders (Belgium). 1 model. Detailed comparisons with recent experimental data in the Pb region are amply discussed.
Nuclear binding energies: global collective structures and local shell-model correlations
2003
Nuclear binding energies and two-neutron separation energies are analysed starting from the liquid-drop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently concentrate on the Interacting Boson Model (IBM) and discuss a new method in order to provide a consistent description of both, ground-state and excitedstate properties. We address the artefacts that appear when crossing midshell using the IBM formulation and perform detailed numerical calculations for nuclei situated in the 50−82 shell. We also concentrate on local deviations from the above global trends in binding energy and two-neutron separation energies that appear in the neutron-deficient Pb region. We address possible effects on the binding energy, caused by mixing of low-lying 0 + intruder states into the ground state, using configuration mixing in the IBM framework. We also study ground-state properties using a macroscopic-microscopic * Postdoctoral fellow of the Fund for Scientific Research-Flanders (Belgium). † Visiting postdoctoral fellow of the Fund for Scientific Research-Flanders (Belgium). 1 model. Detailed comparisons with recent experimental data in the Pb region are amply discussed.
Large-scale shell model calculations of the 25,26Mg, 27Al and 19F nucleus
International Journal of Nuclear Energy Science and Technology, 2018
Shell model calculations were performed to study the energy levels for the 25,26 Mg and 27 Al nuclei by employing the sdpfnow effective interaction with the large-scale sdpf model space by using the shell model code NuShell@MSU for Windows. The electron scattering form factors for 19 F nucleus also have been studied with and without effective charge on the sdpfmodel space and Tassie model. The Harmonic Oscillator and Skyrme potentials have been used to calculate the wave functions of radial single-particle matrix elements. The level schemes are compared with the experimental data. Coulomb and magnetic form factors in the present work include the transitions from ground state (1/2 + 1/2) to the (7/2 + 1/2), (9/2 + 1/2), (3/2-1/2), and (11/2-1/2) states in 19 F. Good agreements were obtained for all nuclei under study for energy levels and form factors comparing with the available experimental data.
The Role of Shell Model in Determining Pairing Interaction in Nuclei
The role of the shell model in pairing interaction in nuclei is investigated by calculating the pairing energies of O-O (odd-odd), O-E (odd-even), E-E (even-even) and E-O (even-odd) isotopes of four elements namely; 15P, 25Mn, 40Zr and 60Nd. The pairing energies were computed using the values of binding energy (B) obtained from AME2016 atomic mass evaluation. The graphs of the pairing energies against the mass numbers revealed an increase of the pairing energies with the occurrence of periodic humps adjacent to the neutron magic numbers. The rise in the pairing energies is attributed to the bound states of heavy nuclei arising from the neutron-neutron pairs in the shell structures beyond the Fermi-surface, while in the light and intermediate nuclei, the rise in the pairing energies is due to the increase in the number of nucleons occupying the surface region. These neutron-neutron pairs formed beyond the Fermi-surface of nuclei of heavy elements have greater pairing energies, which contribute to greater binding energies associated with the heavy elements found in the neutron stars. It is concluded that the shell model can predict the existence of isotopes of heavy elements in the neutron stars and the criterion to ascertain their existence lies on the pairing energies. Calculations show that the isotopes with highest peaks among the heavy elements can predict the most abundant isotopes of the heavy elements in the neutron stars, for instance, 90 Zr, 91 Zr, 142 Nd, 145 Nd, 146 Nd, 148 Nd and 150 Nd nuclei.
Full 0homega shell model calculation of the binding energies of the 1f7/2 nuclei
Physical Review C, 1999
Binding energies and other global properties of nuclei in the middle of the pf shell, such as M1, E2 and Gamow-Teller sum rules, have been obtained using a new Shell Model code (NATHAN) written in quasi-spin formalism and using a j-j-coupled basis. An extensive comparison is made with the recently available Shell Model Monte Carlo results using the effective interaction KB3. The binding energies for -nearly-all the 1f 7/2 nuclei are compared with the measured (and extrapolated) results.
Shell-model Monte Carlo studies of neutron-rich nuclei in the 1s-0d-1p-0f shells
Physical Review C, 1999
We demonstrate the feasibility of realistic Shell-Model Monte Carlo (SMMC) calculations spanning multiple major shells, using a realistic interaction whose bad saturation and shell properties have been corrected by a newly developed general prescription. Particular attention is paid to the approximate restoration of translational invariance. The model space consists of the full sd-pf shells. We include in the study some well-known T =0 nuclei and several unstable neutron-rich ones around N = 20, 28. The results indicate that SMMC can reproduce binding energies, B(E2) transitions, and other observables with an interaction that is practically parameter free. Some interesting insight is gained on the nature of deep correlations. The validity of previous studies is confirmed.
Shell model calculations on even nuclei near 208Pb
International Journal of Physical Sciences, 2012
208 Pb. The binding energy calculations were in good agreement with experimental data. The predicted low-lying levels (energies, spins and parities) and B(E2) values results were reasonably consistent with the available experimental data. Truncation model space was applied on the 202 Au isotope, where πg7/2 and νh9/2 kept filling as well as νh9/2 for 202 Hg and 202 Tl.
Nuclear Physics A, 1974
A shell model calculation in an enlarged space spanned by two particles in the (2s, ld) shell and three-particle-one-hole 2h~o excitations is performed using the "bare" G-matrix. An effective interaction for the (2s, ld) shell is generated and its convergence properties are investigated. It is maintained that the series converges reasonably fast in G and that the singleparticle energies used in the calculation are instrumental in this respect. This conclusion is corroborated by the E2 effective charges and B(E2) strengths that we compute for A = 17 and A = 18 nuclei respectively. * See ref. 2) for a complete list of references. 171