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 Quadrupole moments of exotic carbon isotopes (9C, 11C, 17C and 19C) including core polarization effect

2019 ◽  
Vol 12 (24) ◽  
pp. 110-121
Author(s):  
Wael A. Saeed A. Saeed
Keyword(s):  
Theoretical Data ◽  
Microscopic Theory ◽  
Quadrupole Moments ◽  
Matrix Elements ◽  
Oscillator Potential ◽  
Core Polarization ◽  
Model Calculations ◽  
Harmonic Oscillator Potential ◽  
Polarization Effects ◽  
Major Shell

Quadrupole Q moments and effective charges are calculated for 9C, 11C, 17C and 19C exotic nuclei using shell model calculations. Excitations out of major shell space are taken into account through a microscopic theory which are called core-polarization effects. The simple harmonic oscillator potential is used to generate the single particle matrix elements of 9,11,17,19C. The present calculations with core-polarization effects reproduced the experimental and theoretical data very well.

Microscopic Large Scale psd Shell Model with M3Y Residual Interaction to Calculate Electron Scattering Form Factors

2017 ◽  
Vol 6 (1) ◽  
pp. 56-61
Author(s):  
Khalid S. Jassim ◽  
Rawaa A. Abdul-Nabe
Keyword(s):  
Shell Model ◽  
Electron Scattering ◽  
Large Scale ◽  
Theoretical Calculations ◽  
Form Factors ◽  
Scale Model ◽  
Core Polarization ◽  
Model Calculations ◽  
Polarization Effects ◽  
Realistic Interaction

The longitudinal and the transverse electron scattering form factors for 6Li, 9Be, 11B and 12C nuclei have been studied with and without core polarization effects using shell model calculations. The psdmwk is used as effective interaction for psd-shells. The core-polarization effects are calculated in the first-order perturbation theory including excitations up to 4ħω using the Michigan three-range Yakawa M3Y as a realistic interaction. The wave functions of radial single particle matrix elements have been calculated with harmonic oscillator potential. For all nuclei under studying, Comparison between experimental and theoretical calculations show that the form factors with core-polarization effect calculations give good consistency with experiment data. So we concluded that the large scale model space enhanced the results to become closed to the experimental data.

scholarly journals Microscopic calculations of the electric Quadrupole transition strengths of Be isotopes (9, 10, 12, 14)

2019 ◽  
Vol 12 (24) ◽  
pp. 87-99
Author(s):  
Sara. H. Ibrahim
Keyword(s):  
Harmonic Oscillator ◽  
Shell Model ◽  
Electric Quadrupole ◽  
Transition Strength ◽  
Matrix Elements ◽  
Core Polarization ◽  
Model Calculations ◽  
Polarization Effects ◽  
The Core ◽  
Effective Charges

Electric Quadrupole transitions are calculated for beryllium isotopes (9, 10, 12 and 14). Calculations with configuration mixing shell model usually under estimate the measured E2 transition strength. Although the consideration of a large basis no core shell model with 2ℏtruncations for 9,10,12 and14 where all major shells s, p, sd are used, fail to describe the measured reduced transition strength without normalizing the matrix elements with effective charges to compensate for the discarded space. Instead of using constant effective charges, excitations out of major shell space are taken into account through a microscopic theory which allows particle–hole excitations from the core and model space orbits to all higher orbits with 2ℏw excitations which are called core-polarization effects. The two body Michigan sum of three ranges Yukawa potential (M3Y) is used for the core-polarization matrix element. The simple harmonic oscillator potential is used to generate the single particle matrix elements of all isotopes considered in this work. The b value of each isotope is adjusted to reproduce the experimental matter radius, These size parameters of the harmonic oscillator almost reproduce all the root mean square (rms) matter radii for 9,10,12,14Be isotopes within the experimental errors. Almost same effective charges are obtained for the neutron- rich Be isotopes which are smaller than the standard values. The major contribution to the transition strength comes from the core polarization effects. The present calculations of the neutron-rich 12,14Beisotopes show a deviation from the general trends in accordance with experimental and other theoretical studies. The configurations arises from the shell model calculations with core-polarization effects reproduce the experimental B(E2) values.

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.

Calculations of Gamow–Teller Transition Strengths in fp-Shell Nuclei Using Shell Model

2020 ◽  
pp. 1-5
Author(s):  
Fouad A. Majeed ◽  
Sarah M. Obaid
Keyword(s):  
Shell Model ◽  
Theoretical Calculations ◽  
Model Space ◽  
Exchange Reactions ◽  
Model Calculations ◽  
Effective Interactions ◽  
Mechanisms Of Formation ◽  
Nuclear Structures ◽  
The Individual ◽  
Gamow Teller

The Gamow–Teller (GT) strength transitions in nuclear structures and astrophysical processes proved to be very important to understand the mechanisms of formation of neutron stars and black holes, therefore the GT transitions in the 46Ti→46V, 47Ti→47V, 48Ti→48V, and 50Cr→50Mn charge-exchange reactions have been studied. The shell model calculations have been carried out in the fp-model space without any restrictions using the GXFP1A, KB3G, and FPD6 effective interactions. The calculation of the GT distribution is compared with recent available experimental data. The theoretical calculations are in reasonably good agreement with the experimental GT distributions and with the summed transition strengths B(GT). For the individual transformations we have reached a qualitative agreement, while the measured cumulative transformation strengths are closely matched by the observed ones.

Shell model study of nuclear structure in 63,65,67Ga

2020 ◽  
Vol 29 (07) ◽  
pp. 2050045
Author(s):  
U. S. Ghosh ◽  
B. Mukherjee ◽  
S. Rai
Keyword(s):  
Shell Model ◽  
Nuclear Structure ◽  
Model Space ◽  
Excitation Energies ◽  
Model Calculations ◽  
Model Study ◽  
Protons And Neutrons ◽  
Experimental Values ◽  
Good Agreement

Shell model calculations have been performed in [Formula: see text] model space using two different interactions viz. jj44bpn and jun45pn to explore nuclear structure in [Formula: see text]Ga. Calculated excitation energies are compared with previously reported experimental values and a good agreement has been observed. Transitions strengths are also calculated using two sets of effective charges for proton and neutron and are compared with nearby [Formula: see text]Zn isotopes. Occupation probabilities of protons and neutrons corresponding to individual orbitals (namely [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] orbital), and dominant particle configurations for individual spin states have been presented as well. Calculations suggest major role of intruder [Formula: see text] orbital in constructing the wave functions of higher angular momentum states, whereas, the lower excited states are mainly dominated by contributions from [Formula: see text] orbitals.

scholarly journals Nuclear structure study of [22,24]Ne and [24]Mg nuclei

2019 ◽  
Vol 65 (2) ◽  
pp. 159
Author(s):  
Fouad A. Majeed ◽  
And Sarah M. Obaid
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Nuclear Structure ◽  
Transition Probabilities ◽  
Form Factors ◽  
Model Space ◽  
High Energy ◽  
Core Polarization ◽  
Model Calculations ◽  
The Core

Shell model calculations based on large basis has been conducted to study the nuclear structure of $^{20}Ne$, $^{22}Ne$ and $^{24}Mg$ nuclei. The energy levels, inelastic electron scattering form factors and transition probabilities are discussed by considering the contribution of  configurations with high-energy beyond the model space of sd-shell model space which is denoted as the core polarization (CP) effects.~The Core polarization is considered by taking the excitations of nucleus from the $1s$ and $1p$ core orbits and also from the valence $2s$ $1d$ shell orbit in to higher shells with $4\hbar\omega$. The effective interactions $USDA$ and $USDB$ are employed with $sd$ shell model space to perform the calculation and the core polarization are calculated with $MSDI$ as residual interaction.~The calculated energy level schemes,  form factors and transition probabilities were compared with the corresponding experimental data. The effect of core polarization is found very important for the calculation of $B(C2)$, $B(C4)$ and form factors, and gives excellent results in comparison with the experimental data without including any adjustable parameters.

scholarly journals NUCLEAR STRUCTURE STUDY AROUND Z = 28

2012 ◽  
Vol 21 (01) ◽  
pp. 1250007 ◽  
Author(s):  
P. C. SRIVASTAVA ◽  
I. MEHROTRA
Keyword(s):  
Shell Model ◽  
Nuclear Structure ◽  
State Of The Art ◽  
Model Space ◽  
Structure Study ◽  
Model Calculations ◽  
Nuclear Structure Study ◽  
Experimental Values ◽  
Cu And Zn ◽  
Zn Isotopes

Yrast levels of Ni , Cu and Zn isotopes for 40 ≤ N ≤ 50 have been described by state-of-the-art shell model calculations with three recently available interactions using 56 Ni as a core in the f5/2pg9/2 model space. The results are unsatisfactory viz. large E(2+) for very neutron-rich nuclei, small B(E2) values in comparison to experimental values. These results indicate an importance of inclusion of πf7/2 and νd5/2 orbitals in the model space to reproduce collectivity in this region.

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