Schalenmodellrechnungen beim Kern O18 mit geschwindigkeitsabhängigen Zwei-Teilchen-Potentialen

1967 ◽  
Vol 22 (4) ◽  
pp. 415-421
Author(s):  
Hans Grote
Keyword(s):  
Experimental Data ◽  
Harmonic Oscillator ◽  
Shell Model ◽  
Interaction Potential ◽  
Ground State ◽  
Wave Functions ◽  
Absolute Position ◽  
Model Calculations ◽  
The Core ◽  
Free Parameters

The energies of the low lying levels and the absolute position of the ground state of the nucleus O18 are calculated using five velocity-dependent potentials. The calculation is based on the shell model with two outer neutrons in the potential of the Ο16 core. The interaction potential as well as the core potential are fitted to experimental data, leaving no free parameters in the final result.The wave functions of the harmonic oscillator are used in each case of the five velocity-dependent potentials. An additional computation is carried out using one of these potentials and taking into account the perturbation of the wave functions. It turns out that, for satisfactory application of the velocity-dependent potentials in shell model calculations, this perturbation should be considered.

Determination of hyperon properties through the variational method considering the hyperfine interaction

2019 ◽  
Vol 28 (10) ◽  
pp. 1950087 ◽  
Author(s):  
S. M. Moosavi Nejad ◽  
A. Armat
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Ground State ◽  
Radiative Decay ◽  
Magnetic Moments ◽  
Wave Functions ◽  
Decay Widths ◽  
Free Parameters ◽  
Theoretical Results

Performing a fit procedure on the hyperon masses, we first determine the free parameters in the Cornell-like hypercentral potential between the constituent quarks of hyperons in their ground state. To this end, using the variational principle, we apply the hyperspherical Hamiltonian including the Cornell-like hypercentral potential and the perturbation potentials due to the spin–spin, spin–isospin and isospin–isospin interactions between constituent quarks. In the following, we compute the hyperon magnetic moments as well as radiative decay widths of spin-3/2 hyperons using the spin-flavor wave function of hyperons. Our analysis shows acceptable consistencies between theoretical results and available experimental data. This leads to reliable wave functions for hyperons at their ground state.

The octupole deformation of 143Ba

2015 ◽  
Vol 24 (11) ◽  
pp. 1550081 ◽  
Author(s):  
Yong-Jing Chen ◽  
Yong-Shou Chen ◽  
Zao-Chun Gao ◽  
Ya Tu
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Ground State ◽  
Wave Functions ◽  
Rotational Bands ◽  
Octupole Deformation ◽  
Quantum Numbers

Based on existence of the octupole deformation in the intrinsic states, the experimentally observed four rotational bands in [Formula: see text]Ba have been well reproduced by the reflection asymmetric shell model (RASM) calculations. Through the analysis of the calculated RASM wave functions, the intrinsic configuration of the observed rotational bands has been assigned as the octupole deformed neutron [Formula: see text] orbit, which is just located below the [Formula: see text] shell gap. The calculated results supported the ground state octupole deformation and the purity of the simplex quantum numbers [Formula: see text] in [Formula: see text]Ba. In addition, the calculated [Formula: see text] values are in agreement with experimental data, and further support the octupole deformation in [Formula: see text]Ba.

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.

scholarly journals New levels in spherical 96Y

2018 ◽  
Vol 27 (06) ◽  
pp. 1850051
Author(s):  
E. H. Wang ◽  
J. H. Hamilton ◽  
A. V. Ramayya ◽  
R. Han ◽  
C. J. Zachary ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Large Deformation ◽  
Ground State ◽  
Spontaneous Fission ◽  
Detector Array ◽  
Model Calculations ◽  
Coincidence Data ◽  
Excited Band ◽  
Good Agreement

New transitions in neutron rich [Formula: see text]Y have been identified by analyzing the high statistics [Formula: see text]-[Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text]-[Formula: see text]-[Formula: see text] coincidence data from the spontaneous fission of [Formula: see text]Cf at the Gammasphere detector array. Shell model calculations were performed and are found in good agreement with experimental data. The ground state is nearly spherical but a new excited band has large deformation.

Study of 18O States by the 17O(d,p)18O Reaction

1975 ◽  
Vol 53 (9) ◽  
pp. 882-890 ◽  
Author(s):  
D. Drain ◽  
B. Chambon ◽  
J. L. Vidal ◽  
A. Dauchy ◽  
H. Beaumevieille
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Cross Sections ◽  
Differential Cross ◽  
Ground State ◽  
Differential Cross Sections ◽  
Model Calculations ◽  
Absolute Differential ◽  
Spectroscopic Factors

The 17O(d,p)18O reaction was studied at Ed = 3.6 and 4.0 MeV. Absolute differential cross sections were measured for the ground state and the 1.98, 3.55, 3.63, 3.91, 4.45, 5.09, 5.25, and 5.37 MeV states in 18O. The experimental data are analyzed using the DWBA and Hauser–Feshbach theoreies and spectroscopic factors are deduced. These results are compared to previous data and shell model calculations. The correspondence between the above states and their analogue states in 18F is discussed.

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.

55 YEARS OF THE SHELL MODEL: A CHALLENGE TO NUCLEAR MANY-BODY THEORY

2005 ◽  
Vol 14 (06) ◽  
pp. 821-844 ◽  
Author(s):  
IGAL TALMI
Keyword(s):  
Shell Model ◽  
Wave Functions ◽  
Many Body ◽  
Apparent Absence ◽  
Model Calculations ◽  
Many Body Theory ◽  
Body Theory ◽  
Nuclear Many Body Theory ◽  
Closed Shells ◽  
Good Agreement

Shell model calculations of nuclear energies and wave functions of nucleons outside closed shells interacting by effective two-body forces yield good agreement with much experimental data. Many attempts have been made to calculate nuclear energies ab initio, by starting from some form of an interaction between free nucleons. Recent results of such calculations claim to obtain reasonable agreement with measured energies. These results, however, are obtained for wave functions which are very complicated. It is difficult to see how such wave functions are consistent with independent nucleon motion, the very essence of the shell model. In some of those calculations, 3-body interactions play a very important role. This is puzzling since nuclear energies are accurately obtained in shell model calculations by using only effective two-body interactions. In this paper, some examples of simple shell model calculations are reviewed. They exhibit good agreement with experiment and the apparent absence of the need for effective 3-body interactions.

scholarly journals An analytical formula for proton momentum distribution in nuclei with A>4

2019 ◽  
Vol 10 ◽  
pp. 248
Author(s):  
G. S. Anagnostatos ◽  
A. N. Antonov ◽  
J. Giapitzakis ◽  
P. Ginis ◽  
S. E. Massen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Momentum Distribution ◽  
Analytical Formula ◽  
Nucleon Nucleon ◽  
Exotic Nuclei ◽  
Wave Functions ◽  
Proton Momentum ◽  
Correlation Effects ◽  
Hartree Fock

A successful analytical formula for the proton momentum distribution in all nuclei with A>4 accounting for nucleon-nucleon correlation effects, is presented. In this formula the Isomorphic Shell Model wave functions are employed, which are readily available for all nuclei all the way up to 2 0 8Pb. However, other wave functions (e.g., shell model or Hartree-Fock) could be used with almost equivalent results. Available experimental data for 4He, 1 2C and 5 6Fe and predictions of other theories, e.g., for 4 0Ca, are used for comparison of the predictions of the present formula. A reservation is kept concerning the validity of this formula for the momentum distribution of exotic nuclei.

scholarly journals Application of single particle model to determine the spin and parity of levels of 59Fe nucleus

2015 ◽  
Vol 18 (1) ◽  
pp. 92-101
Author(s):  
Son An Nguyen ◽  
Lanh Dang
Keyword(s):  
Experimental Data ◽  
Excited State ◽  
Shell Model ◽  
Single Particle ◽  
Ground State ◽  
Particle Model ◽  
Nuclear Shell Model ◽  
Average Mass ◽  
Single Particle Model ◽  
Nuclear Shell

The spin and parity of the excited state and the ground state of nuclei are two of important properties of the nuclei quantum. However, up to now we do not have appropriate equipments to directly detetmine the spin and parity of nuclei. This paper shows the application of nuclear shell model to study the spin and parity of intermediate levels and ground state of 59Fe nucleus. Comparing to previously experimental data, this nucleus singleparticle model is suitable of the average mass and odd A nuclei.

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