Shell-model calculations in the 4He system

1979 ◽  
Vol 57 (11) ◽  
pp. 1833-1837 ◽  
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Binding Energy ◽  
Adequate Description ◽  
Model Calculations ◽  
Level Spectrum ◽  
Consistent Manner ◽  
Model Spaces ◽  
Single Oscillator ◽  
Oscillator Length ◽  
Text Model ◽  
Structure Calculations

Structure calculations for the 4He system are performed in both [Formula: see text] and [Formula: see text] model spaces. The results of these calculations suggest that a reasonable level spectrum can be obtained with the Sussex interaction if binding energy considerations are neglected. Imposing binding energy requirements leads to distortions in the level spectrum. The T = 1 levels and selected T = 0 levels are reasonably described by the bare Sussex interaction (b = 1.4 fm). The (0+, 0) 20.1 MeV level and (2−, 0) 22.1 MeV level are best described by the b = 1.80 fm and b = 1.60 fm Sussex interactions, respectively. Attempts to arbitrarily vary individual relative matrix elements do not improve the (0+, 0) spectrum. The resulting calculations suggest that an adequate description of the 4He level spectrum is not possible if a single oscillator length parameter is used for all levels. The results also emphasize the difficulty of performing structure and reaction calculations in a consistent manner, because different b values are required for binding, rms radius, or level considerations. The choice of b is not obvious and should be determined by solution criteria.

Shell evolution for neutron-rich 46–54Ar isotopes in the full and truncated fp neutron model spaces

2021 ◽  
Author(s):  
Hussam A. Bahr ◽  
Ali A. Alzubadi
Keyword(s):  
Excitation Energy ◽  
Shell Model ◽  
Transition Probability ◽  
Energy Levels ◽  
Drip Line ◽  
Model Calculations ◽  
Effective Interactions ◽  
Argon Isotopes ◽  
Model Spaces ◽  
Text Model

The shell evolution of even–even drip line argon isotopes [Formula: see text] has been investigated via the shell model calculations using SDPF-U and SDPF-NR two-body effective interactions in two different shell model spaces [Formula: see text] and [Formula: see text]. In this work, the energy of first [Formula: see text], reduced transition probability [Formula: see text], excitation energy levels as well as how the proton shells evolve with [Formula: see text] have been studied. Excellent agreements were obtained for the first [Formula: see text] level along the investigated isotopes within [Formula: see text] and [Formula: see text] model spaces.

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.

O 1s Core-Level Positions of Bi2Sr2CaCu2O8-x by OKα-Ray Emission

1989 ◽  
Vol 44 (9) ◽  
pp. 780-784
Author(s):  
F. Burgäzy ◽  
C. Politis ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Binding Energy ◽  
Energy Level ◽  
Photoelectron Spectrum ◽  
Local Density ◽  
Binding Energies ◽  
Core Level ◽  
X Ray ◽  
Band Structure Calculations ◽  
Density Band ◽  
Structure Calculations

Abstract The measured O Kα X-ray emission spectrum of the high-Tc superconductor Bi2Sr2CaCu2O8-x is compared with a spectrum based on local density band structure calculations. By taking also into account the shape of the measured O 1s X-ray photoelectron spectrum an energy level diagram for the O 1s core-level binding energies of the three different oxygen sites is constructed. The O 1s binding energy in the Bi2O2-layers is found to be about the same as that one in the SrO-layers, whereas the binding energy in the CuO2-layers is lower by about 0.5 eV.

scholarly journals The calculation of Binding Energy and Incompressibility, Pressure, and Velocity of Sound of Infinite Nuclear matter Using New One Boson Interaction.

2019 ◽  
Vol 1 ◽  
pp. 288-293
Author(s):  
M T Aper ◽  
F Gbaorun ◽  
J O Fiase
Keyword(s):  
Binding Energy ◽  
Nuclear Matter ◽  
Effective Interaction ◽  
Research Work ◽  
Nucleon Nucleon ◽  
Matrix Approach ◽  
Velocity Of Sound ◽  
Model Calculations ◽  
Effective Interactions

The use of effective nucleon – nucleon (N N) interactions for the determination of nuclear matter properties such as, binding energy per nucleon, incompressibility,K of infinite nuclear matter, pressure 0 and velocity of sound of nuclear matter has been a subject of great interest to nuclear physicists for many decades. The effective interaction usually involved in these calculations has been the Michigan three Yukawa (M3Y) effective interactions whose origin is from G- matrix approach. In this research work however, we have used a newly developed interaction known as new one boson (NOB) effective interaction to carry out similar calculations. This new interaction is based on the Lowest Order Constrained Variational (LOCV) technique. The interaction reproduces the saturation energy of spin and isospin infinite nuclear matter of approximately -16MeV at the normal nuclear matter saturation density consistent with the best available density-dependent interaction derived from the G-matrix approach. The results of the incompressibility obtained using the NOB interaction ranges from 304 to 309 MeV. These values are in good agreement with the values of incompressibility obtained for similar calculations using the M3Y – Reid effective interaction, in which values for K range from 304 to 310 MeV. The results of 0 pressure and velocity of sound of infinite nuclear matter obtained in the present calculations are also in excellent agreement with results of other workers. The results of our present calculations indicate that, the NOB interaction has passed the basic test for an effective interaction. The NOB may therefore be applied to other nuclear matter and optical model calculations to ascertain its reliability.

scholarly journals The γ-ray spectroscopy studies of low-spin structures in 210Bi and 206Tl using cold neutron capture reactions

2018 ◽  
Vol 193 ◽  
pp. 05007
Author(s):  
Natalia Cieplicka-Oryńczak ◽  
Silvia Leoni ◽  
Bogdan Fornal ◽  
Dino Bazzacco ◽  
Aurelien Blanc ◽  
...  
Keyword(s):  
Binding Energy ◽  
Neutron Capture ◽  
Experimental Information ◽  
Neutron Binding Energy ◽  
Model Calculations ◽  
Coincidence Technique ◽  
Spin Structures ◽  
Angular Correlations ◽  
Γ Ray ◽  
Spectroscopy Studies

The γ-coincidence studies of low-spin structures of 210Bi and 206Tl are presented. The 210Bi nucleus, populated in thermal neutron capture reaction, was investigated using EXILL HPGe array at Institut Laue-Langevin in Grenoble. The experimental results were compared to the shell-model calculations allowing to draw the conclusions on the nature of the low-spin excitations populated below the neutron binding energy in 210Bi (4.6 MeV). It has been found that some levels cannot be described by the valence proton and neutron couplings, but may arise from couplings of valence particles to the 3- octupole phonon of the doubly magic 208Pb core. Moreover, preliminary results of a low-spin structure measurements of 206Tl by the γ-coincidence technique, making use of the 205Tl(n,γ)206Tl reaction at the FIPPS prompt γ-ray spectroscopy facility of ILL are shown. The population of a large number of excited states of 206Tl above the ground state up to the neutron binding energy (at 6.5 MeV), within a few units of spin is expected. The analysis involving double and triple γ-coincidences and γγ-angular correlations will allow to significantly extend the experimental information on the energy and spin-parity of the levels in 206Tl. This will help shedding light on the proton-hole and neutron-hole couplings near the doubly magic core 208Pb.

scholarly journals Accelerating many-nucleon basis generation for high performance computing enabled ab initio nuclear structure studies

2019 ◽  
Vol 33 (3) ◽  
pp. 522-533 ◽  
Author(s):  
Daniel Langr ◽  
Tomáš Dytrych ◽  
Kristina D Launey ◽  
Jerry P Draayer
Keyword(s):  
Ab Initio ◽  
Nuclear Structure ◽  
High Performance ◽  
Model Framework ◽  
Significant Acceleration ◽  
Model Spaces ◽  
Basis Construction ◽  
Nuclear Structure Calculations ◽  
Performance Computing ◽  
Structure Calculations

We present the problem of generating a many-nucleon basis in [Formula: see text]-scheme for ab initio nuclear structure calculations in a symmetry-adapted no-core shell model framework. We first discuss and analyze the basis construction algorithm whose baseline implementation quickly becomes a significant bottleneck for large model spaces and heavier nuclei. The outcomes of this analysis are utilized to propose a new scalable version of the algorithm. Its performance is consequently studied empirically using the Blue Waters supercomputer. The measurements show significant acceleration achieved with over two orders of magnitude speedups realized for larger model spaces.

SHELL MODEL CALCULATIONS OF 3T, 5He AND 6Li NUCLEI

2002 ◽  
Vol 11 (01) ◽  
pp. 67-70
Author(s):  
NAZIH EL-NOHY
Keyword(s):  
Binding Energy ◽  
Shell Model ◽  
Root Mean Square ◽  
Long Range ◽  
Ground State ◽  
Radial Dependence ◽  
Spin Orbit ◽  
Mean Square ◽  
Model Calculations ◽  
Short Range Repulsion

The bases of the translation invariant shell model are used to construct the ground-state wave functions of 3 T , 5 He and 6 Li . For 3 T the bases used correspond to the number of quanta of excitation N up to ten. For 5 He and 6 Li the bases used correspond to the number of quanta of excitation N up to six. The model is applied to calculate the binding energy and the root mean square radius for 3 T , 5 He and 6 Li nuclei. The residual interactions used consist of central, tensor, spin-orbit and quadratic spin-orbit terms with Gaussian radial dependence. The parameters of these interactions are chosen in such away that they represent the long range attraction and the short range repulsion of nucleon interactions. It was found that this potential is more suitable for calculating the characteristics of these nuclei, and better than other potentials, such as our previous potentials which were represented by the parameters of long range attraction forces only. For 3T we obtained good agreement between calculated and experimental values of both the ground state binding energy and the root mean square radius. For 5 He and 6 Li nuclei we obtained an acceptable improvement with these calculations over other potentials.

Physics of Charged Mgn (n≤7) and Mixed MgnKy (x+y≤4) Clusters

1990 ◽  
Vol 206 ◽  
Author(s):  
S. N. Khanna ◽  
F. Reuse ◽  
V. de Coulon ◽  
J. Buttet
Keyword(s):  
Electronic Structure ◽  
Binding Energy ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Atomic Orbitals ◽  
The Core ◽  
Non Local ◽  
The Stability ◽  
Mixed Clusters ◽  
Structure Calculations

ABSTRACTElectronic structure calculations on neutral and charged Mgn (n≤7) clusters and KnMgm mixed clusters have been carried out within a linear combination of atomic orbitals molecular orbital approach. The exchange correlaton effects have been treated via local spin density functional and non-local pseudopotentials have been used to replace the core. Our studies on charged Mgn clusters focus on the electron affinity and atomic binding in anionic clusters and the stability and observability of doubly ionized clusters. In KnMgm clusters, we have considered the evolution of the electronic spectrum and the variation of the binding energy with size and composition.

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