Shell model description of the 0+ and 0− excited states in sd shell nuclei

2018 ◽  
Vol 96 (7) ◽  
pp. 774-778 ◽  
Author(s):  
M. Bouhelal ◽  
N. Saidane ◽  
S. Belaid ◽  
F. Haas
Keyword(s):  
Shell Model ◽  
Excited States ◽  
Ground State ◽  
Model Description ◽  
Excitation Energies ◽  
Model Calculations ◽  
The Future

The purpose of this work is to describe, in light of shell model calculations using the PSDPF interaction, the particular states with J = 0 in sd shell nuclei. These states are difficult to observe. It is well known that the ground state in even–even nuclei has Jπ = 0+ and therefore we are interested in describing their first excited [Formula: see text] states. We have also studied the first and second excited 0− states in all sd nuclei. The experimental and theoretical excitation energies of these states were confronted. This study allowed us to make predictions of the existence of [Formula: see text] and (or) [Formula: see text] states in nuclei, which do not possess these states, or to have an idea of their excitation energies for possible experiments in the future.

scholarly journals Single-Particle and Collective Structures in Neutron-Rich Sr Isotopes

Universe ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Kamila Sieja
Keyword(s):  
Shell Model ◽  
Ground State ◽  
Experimental Studies ◽  
Low Energy ◽  
Model Description ◽  
Sr Isotopes ◽  
Model Calculations ◽  
Spectroscopic Factors ◽  
Monte Carlo Shell Model ◽  
Insight Into

Neutron-rich Sr nuclei around N=60 exhibit a sudden shape transition from a spherical ground state to strongly prolate-deformed. Recently, much new insight into the structure of Sr isotopes in this region has been gained through experimental studies of the excited levels, transition strengths, and spectroscopic factors. In this work, a “classic” shell model description of strontium isotopes from N=50 to N=58 is provided, using a natural valence space outside the 78Ni core. Both even–even and even–odd isotopes are addressed. In particular, spectroscopic factors are computed to shed more light on the structure of low-energy excitations and their evolution along the Sr chain. The origin of deformation at N=60 is mentioned in the context of the present and previous shell model and Monte Carlo shell model calculations.

scholarly journals Wigner SU(4) symmetry, clustering, and the spectrum of $$^{12}$$C

2021 ◽  
Vol 57 (9) ◽  
Author(s):  
Shihang Shen ◽  
Timo A. Lähde ◽  
Dean Lee ◽  
Ulf-G. Meißner
Keyword(s):  
Excited States ◽  
Ground State ◽  
Nucleon Nucleon ◽  
Irreducible Representations ◽  
Spin Orbit ◽  
Hoyle State ◽  
Nucleon Interaction ◽  
Model Calculations ◽  
Nucleon Nucleon Interaction ◽  
Spin Orbit Interactions

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.

SHAPE EVOLUTION OF HIGHLY DEFORMED 75Kr AND PROJECTED SHELL MODEL DESCRIPTION

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1754-1762 ◽  
Author(s):  
YING-CHUN YANG ◽  
YANG SUN ◽  
T. TRIVEDI ◽  
R. PALIT ◽  
J. A. SHEIKH
Keyword(s):  
Shell Model ◽  
Negative Parity ◽  
Model Description ◽  
Shape Evolution ◽  
Quadrupole Moments ◽  
Projected Shell Model ◽  
Model Calculations ◽  
High Spin States ◽  
Parity Band ◽  
Insight Into

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 .

The ground state and low-lying excited states of CCCN radical and its ions: a CASSCF/CASPT2 study

2016 ◽  
Vol 94 (9) ◽  
pp. 803-807
Author(s):  
Angyang Yu
Keyword(s):  
Excited States ◽  
Ground State ◽  
Linear Structure ◽  
Electronic Configuration ◽  
Geometric Optimization ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Excitation Energies ◽  
Complete Active Space ◽  
Vertical Excitation

The ground state and low-lying excited states of the CCCN radical and its ions have been investigated systematically using the complete active space self-consistent field (CASSCF) and multi-configuration second-order perturbation theory (CASPT2) methods in conjunction with the ANO-RCC-TZP basis set. The calculated results show that the state 12Σ+ has the lowest CASPT2 energy among the electronic states. By means of the geometric optimization of this radical, it could be found that the molecule exhibits linear structure, with the bond lengths R1 = 1.214 Å, R2 = 1.363 Å, R3 = 1.162 Å, which are very close to the experimental values. The calculated vertical excitation energies and the corresponding oscillator strengths show that there are three relatively strong peaks at energies 0.63, 4.04, and 5.49 eV, which correspond to the transitions 12Σ+ → 12Π, 12Σ+ → 22Π, and 12Σ+ → 22Σ+, respectively. Additionally, the electronic configuration and the harmonic vibration frequencies of each state are also investigated.

FIRST γ-RAY SPECTROSCOPY AND ISOSPIN SYMMETRY STUDY OF THE N = Z - 2 NUCLEUS 44V

2010 ◽  
Vol 25 (21n23) ◽  
pp. 2028-2029 ◽  
Author(s):  
M. J. TAYLOR ◽  
M. A. BENTLEY ◽  
J. BROWN ◽  
R. WADSWORTH ◽  
P.E. KENT ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Shell Model ◽  
Excited States ◽  
State Of The Art ◽  
Isospin Symmetry ◽  
Charge Symmetry Breaking ◽  
Charge Symmetry ◽  
Model Calculations ◽  
Γ Ray ◽  
First Time

Excited states in the Tz = -1 nucleus 44 V have been observed for the first time. The states have been identified through recoil-γ-γ coincidences and comparison with analogue states in the mirror nucleus 44 Sc . Mirror energy differences have been extracted and compared to state-of-the-art fp shell-model calculations which include charge symmetry breaking forces.

CHAMELEON GROUND STATE AND EXCITED STATES OF EDT-TTF-IM-F4TCNQ RADICAL DYAD IN DIFFERENT ENVIRONMENTS

2012 ◽  
Vol 11 (03) ◽  
pp. 505-525 ◽  
Author(s):  
YUHUA ZHOU ◽  
KAI TAN ◽  
XIN LU
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Solvent Polarity ◽  
Functional Study ◽  
Polar Solvents ◽  
Model Calculations ◽  
A Charge

We have performed a systematic density functional study on the ground-state electronic structure and excited states of a representative D-σ-A dyad, i.e. EDT-TTF-Im-F4TCNQ π-radical, in vacuo and in different conventional solvents (toluene, THF, DMF and DMSO) by using some popular hybrid density functionals (B3LYP, M05, M05-2X, PBE0 and BMK). It has been shown that the M05 and B3LYP functionals perform the best in predicting the intramolecular charge-transfer (ICT) pertaining to both the ground state and excited states of the dyad. The amphoteric dyad is liable to solvent-promoted ICT from its EDT-TTF-Im donor (D) to F4TCNQ acceptor (A), adopting a charge-unseparated ground state D-A• in vacuo, a partially zwitterionic ground state [D-A]• in nonpolar toluene solvent, and a fully zwitterionic ground state D•+-A- in such polar solvents as THF, DMF and DMSO. Owing to its solvent-dependent chameleon ground state, excited states of the dyad in solvents also exhibit remarkable dependence on solvent polarity, as revealed by TDDFT calculations. Furthermore, cluster model calculations revealed that intermolecular charge-transfer readily occurs between the dyads, accounting for the observed zwitterionic charge state in solid state and solid-state semiconductivity.

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.

MR-CISD and MR-AQCC Calculation of Excited States of Malonaldehyde: Geometry Optimizations Using Analytical Energy Gradient Methods and a Systematic Investigation of Reference Configuration Sets

2003 ◽  
Vol 68 (3) ◽  
pp. 447-462 ◽  
Author(s):  
Silmar A. do Monte ◽  
Michal Dallos ◽  
Thomas Müller ◽  
Hans Lischka
Keyword(s):  
Excited States ◽  
Ground State ◽  
Transition Energy ◽  
Gradient Methods ◽  
Systematic Investigation ◽  
Oscillator Strengths ◽  
Excitation Energies ◽  
Band Maximum ◽  
Vertical Excitation ◽  
Energy Gradient

Extended MR-CISD and MR-AQCC calculations have been performed on the ground state and the first two excited states of malonaldehyde. Full geometry optimizations have been carried for Cs and C2v structures both at MR-CISD and MR-AQCC levels. Vertical and minimum-to-minimum excitation energies and oscillator strengths have been computed. Systematic studies have been undertaken concerning several types of reference spaces. Agreement with the experimental 0-0 transition energy to the S1 state (expt. 3.50 eV, calc. 3.56 eV) and for the vertical excitation to S2 (expt. band maximum 4.71 eV, best estimate 4.86 eV) is very good. In agreement with the CASSCF/CASPT2 results by Sobolewski and Domcke (J. Phys. Chem. A 1999, 103, 4494), we find that the hydrogen bond in malonaldehyde is weakened by excitation to the S1 state. The barrier for proton transfer in the S1 state is increased in comparison with the ground state.

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.

scholarly journals Jacobi no-core shell model for p-shell hypernuclei

2020 ◽  
Vol 56 (12) ◽  
Author(s):  
Hoai Le ◽  
Johann Haidenbauer ◽  
Ulf-G. Meißner ◽  
Andreas Nogga
Keyword(s):  
Renormalization Group ◽  
Shell Model ◽  
Excited States ◽  
Nucleon Nucleon ◽  
Nucleon Pair ◽  
Core Shell ◽  
Excitation Energies ◽  
Fractional Parentage ◽  
Data Files ◽  
The Spectator

AbstractWe extend the recently developed Jacobi no-core shell model to hypernuclei. Based on the coefficients of fractional parentage for ordinary nuclei, we define a basis where the hyperon is the spectator particle. We then formulate transition coefficients to states that single out a hyperon–nucleon pair which allow us to implement a hypernuclear many-baryon Hamiltonian for p-shell hypernuclei. As a first application, we use the basis states and the transition coefficients to calculate the ground states of $$^{4}_{\varLambda }\hbox {He}$$ Λ 4 He , $$^{4}_{\varLambda }\hbox {H}$$ Λ 4 H , $$^{5}_{\varLambda }\hbox {He}$$ Λ 5 He , $$^{6}_{\varLambda }\hbox {He}$$ Λ 6 He , $$^{6}_{\varLambda }\hbox {Li}$$ Λ 6 Li , and $$^{7}_{\varLambda }\hbox {Li}$$ Λ 7 Li and, additionally, the first excited states of $$^{4}_{\varLambda }\hbox {He}$$ Λ 4 He , $$^{4}_{\varLambda }\hbox {H}$$ Λ 4 H , and $$^{7}_{\varLambda }\hbox {Li}$$ Λ 7 Li . In order to obtain converged results, we employ the similarity renormalization group (SRG) to soften the nucleon–nucleon and hyperon-nucleon interactions. Although the dependence on this evolution of the Hamiltonian is significant, we show that a strong correlation of the results can be used to identify preferred SRG parameters. This allows for meaningful predictions of hypernuclear binding and excitation energies. The transition coefficients will be made publicly available as HDF5 data files.

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