scholarly journals Large–scale shell model calculations for 140Xe

2018 ◽  
Vol 194 ◽  
pp. 01004
Author(s):  
Sevdalina Dimitrova ◽  
Nicola Lo Iudice

This paper presents the results of a large-scale shell model calculations of the yrast spectrum of 140Xe. We extend the previous calculations confined to low-lying angular momenta to high-spin states apply- ing the same importance sampling iterative matrix diagonalization algorithm. Excitation energies and transi- tion probabilities are obtained by using an effective nucleon-nucleon interaction derived from the CD-Bonn nucleon-nucleon potential. A satisfactory agreement with the experimental data and the previous results for low lying states is achieved.

Author(s):  
Noritaka Shimizu ◽  
Tomoaki Togashi ◽  
Yutaka Utsuno

Abstract β-decay half-lives of neutron-rich nuclei around N = 82 are key data to understand the r-process nucleosynthesis. We performed large-scale shell-model calculations in this region using a newly constructed shell-model Hamiltonian, and successfully described the low-lying spectra and half-lives of neutron-rich N = 82 and N = 81 isotones with Z = 42 − 49 in a unified way. We found that their Gamow-Teller strength distributions have a peak in the low-excitation energies, which significantly contributes to the half-lives. This peak, dominated by ν0g7/2 → π0g9/2 transitions, is enhanced on the proton deficient side because the Pauli-blocking effect caused by occupying the valence proton 0g9/2 orbit is weakened.


2015 ◽  
Vol 91 (2) ◽  
Author(s):  
Tomoaki Togashi ◽  
Noritaka Shimizu ◽  
Yutaka Utsuno ◽  
Takaharu Otsuka ◽  
Michio Honma

2013 ◽  
Vol 445 ◽  
pp. 012028 ◽  
Author(s):  
Y Tsunoda ◽  
T Otsuka ◽  
N Shimizu ◽  
M Honma ◽  
Y Utsuno

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov

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.


2021 ◽  
Vol 57 (9) ◽  
Author(s):  
Shihang Shen ◽  
Timo A. Lähde ◽  
Dean Lee ◽  
Ulf-G. Meißner

AbstractWe present lattice calculations of the low-lying spectrum of $$^{12}$$ 12 C using a simple nucleon–nucleon interaction that is independent of spin and isospin and therefore invariant under Wigner’s SU(4) symmetry. We find strong signals for all excited states up to $$\sim 15$$ ∼ 15  MeV above the ground state, and explore the structure of each state using a large variety of $$\alpha $$ α cluster and harmonic oscillator trial states, projected onto given irreducible representations of the cubic group. We are able to verify earlier findings for the $$\alpha $$ α clustering in the Hoyle state and the second $$2^+$$ 2 + state of $$^{12}$$ 12 C. The success of these calculations to describe the full low-lying energy spectrum using spin-independent interactions suggest that either the spin-orbit interactions are somewhat weak in the $$^{12}$$ 12 C system, or the effects of $$\alpha $$ α clustering are diminishing their influence. This is in agreement with previous findings from ab initio shell model calculations.


2010 ◽  
Vol 19 (08n09) ◽  
pp. 1754-1762 ◽  
Author(s):  
YING-CHUN YANG ◽  
YANG SUN ◽  
T. TRIVEDI ◽  
R. PALIT ◽  
J. A. SHEIKH

A study of recently-measured high spin states of 75 Kr is carried out by using the Projected Shell Model. Calculations are performed up to spin I = 33/2 for the positive parity band and I = 27/2 for the negative parity band. Irregularities found in moment of inertia and in the deduced transition quadrupole moments Q t of the two bands are discussed in terms of the alignment of g 9/2 protons. Our study provides an insight into the shape evolution of the well-deformed nucleus 75 kr .


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