A boson approach to the structure of A=22 nuclei

Open Physics ◽  
2003 ◽  
Vol 1 (4) ◽  
Author(s):  
Edward Kwaśniewicz ◽  
Edyta Hetmaniok ◽  
Jakub Brzostowski ◽  
Francesco Catara ◽  
Michelangelo Sambataro
Keyword(s):  
Shell Model ◽  
Model Space ◽  
Pauli Principle ◽  
Fermion System ◽  
Model Calculations ◽  
Major Shell

AbstractWe discuss a procedure to transfer the description of a fermion system from a subspace of the full shell model space built in terms of collective pairs onto a space of corresponding bosons. We apply the procedure to systems of six nucleons in the 1s0d major shell. We perform exact shell model calculations and compare them with calculations in the collective pair and boson approximations. The effects of the truncation of the boson Hamiltonian and of the consequent violation of the Pauli principle are examined.

scholarly journals Study of the Electric Quadrupole Moments for some Scandium Isotopes Using Shell Model Calculations with Different Interactions

2018 ◽  
Vol 15 (3) ◽  
pp. 304-309
Author(s):  
Baghdad Science Journal
Keyword(s):  
Shell Model ◽  
Theoretical Calculations ◽  
Microscopic Theory ◽  
Model Space ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Core Polarization ◽  
Model Calculations ◽  
Major Shell ◽  
Experimental Values

The electric quadrupole moments for some scandium isotopes (41, 43, 44, 45, 46, 47Sc) have been calculated using the shell model in the proton-neutron formalism. Excitations out of major shell model space were taken into account through a microscopic theory which is called core polarization effectives. The set of effective charges adopted in the theoretical calculations emerging about the core polarization effect. NushellX@MSU code was used to calculate one body density matrix (OBDM). The simple harmonic oscillator potential has been used to generate the single particle matrix elements. Our theoretical calculations for the quadrupole moments used the two types of effective interactions to obtain the best interaction compared with the experimental data. The theoretical results of the quadrupole moments for some scandium isotopes performed with FPD6 interaction and Bohr-Mottelson effective charge agree with experimental values.

scholarly journals Large Scale Shell Model Calculations of the Negative-Parity States Structure in 24Mg Nucleus

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Energy Levels ◽  
Form Factors ◽  
Model Space ◽  
Negative Parity ◽  
Matrix Elements ◽  
Model Calculations

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.

scholarly journals Shell-model calculations for upper pf-shell nuclei with an effective interaction

2018 ◽  
Vol 194 ◽  
pp. 01006
Author(s):  
Kalin Drumev
Keyword(s):  
Shell Model ◽  
Effective Interaction ◽  
Model Space ◽  
Model Calculations ◽  
Energy Eigenstates ◽  
Mixed Symmetry ◽  
Symmetry Approach ◽  
Oscillator Shell ◽  
Single Oscillator ◽  
Pf Shell

Results obtained for the energy spectra and the low-lying positive-parity energy eigenstates of the upper p f -shell nuclei 64Ge and 68Se with the use of the effective interaction JUN45 are reported. We address the question of how appropriate is the possibility to construct a symmetry-adapted shell model in a single oscillator shell using a Pairing-plus-Quadrupole Hamiltonian. Specifically, we study the goodness of the symmetries pseudo SU(3) and O(6) in the structure of the energy eigenstates. Finally, we relate our results to a proposed mixed-symmetry approach which is able to simultaneously account for the presence of both the pairing and the quadrupole modes as the most important ingredients in the effective interaction while using a restricted part of the full model space.

scholarly journals SHELL MODEL DESCRIPTION OF 102–108Sn ISOTOPES

2012 ◽  
Vol 21 (04) ◽  
pp. 1250049
Author(s):  
T. TRIVEDI ◽  
P. C. SRIVASTAVA ◽  
D. NEGI ◽  
I. MEHROTRA
Keyword(s):  
Shell Model ◽  
Single Particle ◽  
State Of The Art ◽  
Model Space ◽  
Model Description ◽  
Nuclear Shell Model ◽  
Model Calculations ◽  
Particle Orbits ◽  
Recent Experimental Work ◽  
Nuclear Shell

We have performed shell model calculations for neutron deficient even 102-108 Sn and odd 103-107 Sn isotopes in sdg7/2h11/2 model space using two different interactions. The first set of interaction is due to Brown et al. and second is due to Hoska et al. The calculations have been performed using doubly magic 100 Sn as core and valence neutrons are distributed over the single particle orbits 1g7/2, 2d5/2, 2d3/2, 3s1/2 and 1h11/2. In more recent experimental work for 101 Sn [I. G. Darby et al., Phys. Rev. Lett.105 (2010) 162502], the g.s. is predicted as 5/2+ with excited 7/2+ at 172 keV. We have also performed another two set of calculations by taking difference in single particle energies of 2d5/2 and 1g7/2 orbitals by 172 keV. The present state-of-the-art shell model calculations predict fair agreement with the experimental data. These calculations serve as a test of nuclear shell model in the region far from stability for unstable Sn isotopes near the doubly magic 100 Sn core.

scholarly journals Gamow-Teller strengths of some sd-shell nuclei in the shell model framework

2020 ◽  
Vol 66 (3 May-Jun) ◽  
pp. 330 ◽  
Author(s):  
S. M. Obaid ◽  
H. M. Tawfeek
Keyword(s):  
Shell Model ◽  
Model Space ◽  
Transition Strength ◽  
Model Framework ◽  
Model Calculations ◽  
Effective Interactions ◽  
Calculated Distribution ◽  
Gamow Teller ◽  
Sd Model ◽  
Strength Distributions

The nuclear Gamow-Teller (GT) transition strength distributions B(GT)have been studied for some sd-shell nuclei in the (3He, t) charge-exchangereactions. The shell model calculations were performed by employing theUSDA and USDB effective interactions in the sd-model space. The results of B(GT) calculations reproduce the the experimental Gamow-Tellerstrength distributions well, while the calculated distribution of summedGT transition strengths were closely reproduce the observed ones.

scholarly journals Shell model calculations in the A=80-100 mass region and study of double β transitions

2020 ◽  
Vol 1 ◽  
pp. 156
Author(s):  
J. Sinatkas ◽  
L. D. Skouras ◽  
D. Strottman ◽  
J. D. Vergados
Keyword(s):  
Shell Model ◽  
Satisfactory Agreement ◽  
Effective Interaction ◽  
Model Space ◽  
Mass Region ◽  
Least Square ◽  
Matrix Elements ◽  
Model Calculations ◽  
Least Square Fit ◽  
The One

The structure of the Ζ,Ν < 50 nuclei is examined in a model space consisting of the 0g9/2, 1p1/2, 1p3/2 and the 0f5/2 hole orbitals outside the doubly closed 100Sn core. The effective interaction for this model space is derived by introducing second order corrections to the Sussex matrix elements, while the one-hole energies are deduced by a least square fit to the observed levels. The results of the calculation are found to be in very satisfactory agreement with experiment for all nuclei with 38<Ζ<46 but for Ζ<38 this agreement begins to deteriorate. Such a feature possibly indicates the appearance of deformation and the breaking of the Ν=50 core. The wavefunctions of the calculation are used to determine double β matrix elements in the Ge, Se, Sr and Kr isotopes.

scholarly journals Shell Model Calculations for 18,19,20O Isotopes by Using USDA and USDB Interactions

2018 ◽  
Vol 63 (3) ◽  
pp. 189 ◽  
Author(s):  
A. K. Hasan
Keyword(s):  
Shell Model ◽  
Empirical Data ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Model Space ◽  
Magic Nucleus ◽  
Model Calculations ◽  
O Isotopes ◽  
Good Agreement

The shell model (SM) is used to calculate the energy levels and transition probabilities B(E2) for 18,19,20 O isotopes. Two interactions (USDA and USDB) are used in the SDPN model space. We assume that all possible many-nucleon configurations are defined by the 0d5/2, 1s1/2, and d3/2 states that are higher than in 16 O doubly magic nucleus. The available empirical data are in a good agreement with theoretical energy levels predictions. Spins and parities were affirmed for new levels, and the transition probabilities B(E2; ↓) are predicted.

scholarly journals Ab initio no-core shell model study of neutron-rich nitrogen isotopes

2019 ◽  
Vol 2019 (7) ◽  
Author(s):  
Archana Saxena ◽  
Praveen C Srivastava
Keyword(s):  
Shell Model ◽  
Nitrogen Isotopes ◽  
Model Space ◽  
Effective Field ◽  
Core Shell ◽  
Chiral Effective Field Theory ◽  
Model Calculations ◽  
Local Character ◽  
Non Local ◽  
Three Body

Abstract We have calculated the energy spectra for neutron-rich $^{18-22}$N isotopes using the no-core shell model. To calculate the energy spectrum we have used three different $NN$ potentials: inside non-local outside Yukawa (INOY), next-to-next-to-next-leading order (N3LO) from chiral effective field theory, and charge-dependent Bonn 2000 (CDB2K). The INOY potential is a two-body interaction but also has the effect of three-body forces at short range and a non-local character present in it. The calculations have been done at $\hbar\Omega=20$ MeV, 14 MeV, and 12 MeV using INOY, N3LO, and CDB2K potentials, respectively. We have also performed shell model calculations with the YSOX interaction. The results with the INOY interaction show good agreement with the experimental data in comparison to the other three interactions. We have also shown the occupancy of different orbitals involved corresponding to the largest model space ($N_{\rm max} = 4$) in the calculations.

scholarly journals Shell model calculations in the A ~ 100 mass region

2020 ◽  
Vol 6 ◽  
pp. 225
Author(s):  
P. Divari ◽  
L. D. Skouras
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Model Space ◽  
Mass Region ◽  
Matrix Elements ◽  
Model Calculations ◽  
Single Neutron ◽  
Least Squares Fit ◽  
The Matrix ◽  
Inert Core

The properties of nuclei with 39≤Ζ≤47 and Ν=51-52 are investigated in large scale shell-model calculations. The doubly closed nucleus 100Sn is selected as the reference state and the nuclei under examination are described in terms of proton holes and one up two neutrons outside the inert core. The proton holes are distributed in a model space consisting of the orbitals g9/2, p1/2, p3/2 while f5/2 is sometimes also considerd. Similary the model space for the neutron particles in­ cludes the orbitals g7/2, d5/2, d3/2, s1/2 and in certain cases h11/2. The effective two-body interaction and the matrix elements of the effective operators were deter­ mined by introducing second-order corrections to the Sussex matrix elements. The single proton holes as well as the single-neutron energies were treated as parameters which were determined by least-squares fit to the observed levels of 39≤Ζ≤47, Ν=50 and Ν=51 respectively. The results of the calculation were found to be in satisfactory agreement with experimental data and this enable us to make predictions about the properties of some exotic nuclei in the vicinity of 100Sn.

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