MICROSCOPIC SELF-CONSISTENT AND COLLECTIVE MODEL DESCRIPTION OF LOW-ENERGY NUCLEAR STRUCTURE

1989 ◽  
Vol 04 (09) ◽  
pp. 2063-2146 ◽  
Author(s):  
K. HEYDE
Keyword(s):  
Nuclear Structure ◽  
Degrees Of Freedom ◽  
Collective Motion ◽  
Collective Model ◽  
Model Description ◽  
Mixed Symmetry ◽  
Self Consistent ◽  
Closed Shells ◽  
Model Approach

In the present review, an attempt is made to approach the different facets of the nucleus at low excitation energy from both a microscopic, self-consistent and a collective model approach. Some attention is given on how to relate the two “opposite” approaches to nuclear structure. In a final chapter, we discuss some newly appreciated modes in the nucleus that are specific to the proton and neutron degrees of freedom e.g. the study of intruder states near closed shells and the presence of proton-neutron mixed-symmetry collective motion.

Microscopic self‐consistent and collective model description of nuclear structure

1991 ◽  
Author(s):  
K. Heyde ◽  
C. De Coster ◽  
D. Van Neck ◽  
M. Waroquier
Keyword(s):  
Nuclear Structure ◽  
Collective Model ◽  
Model Description ◽  
Self Consistent

scholarly journals Shell model description of heavy nuclei and abnormal collective motions

2018 ◽  
Vol 178 ◽  
pp. 02015
Author(s):  
Chong Qi
Keyword(s):  
Shell Model ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Model Description ◽  
Heavy Nuclei ◽  
Collective Models ◽  
Collective Behaviors ◽  
Electromagnetic Transition ◽  
Nuclear Shell ◽  
Model Approach

In this contribution I present systematic calculations on the spectroscopy and electromagnetic transition properties of intermediate-mass and heavy nuclei around 100Sn and 208Pb. We employed the large-scale configuration interaction shell model approach with realistic interactions. Those nuclei are the longest isotopic chains that can be studied by the nuclear shell model. I will show that the yrast spectra of Te isotopes show a vibrational-like equally spaced pattern but the few known E2 transitions show rotational-like behaviour. These kinds of abnormal collective behaviors cannot be reproduced by standard collective models and provide excellent background to study the competition of single-particle and various collective degrees of freedom. Moreover, the calculated B(E2) values for neutron-deficient and heavier Te isotopes show contrasting different behaviours along the yrast line, which may be related to the enhanced neutron-proton correlation when approaching N=50. The deviations between theory and experiment concerning the energies and E2 transition properties of low-lying 0+ and 2+ excited states and isomeric states in those nuclei may provide a constraint on our understanding of nuclear deformation and intruder configuration in that region.

THE DESCRIPTION AND ROLE OF FLUCTUATIONS IN COLLECTIVE DEGREES OF FREEDOM IN MODELS OF NUCLEAR STRUCTURE BASED ON THE SELF-CONSISTENT MEAN FIELD

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1787-1791
Author(s):  
MICHAEL BENDER ◽  
PAUL-HENRI HEENEN
Keyword(s):  
Nuclear Structure ◽  
Density Functional ◽  
Degrees Of Freedom ◽  
Density Functional Method ◽  
Mean Field ◽  
Functional Method ◽  
Energy Density Functional ◽  
Open Questions ◽  
Self Consistent

This contribution sketches recent efforts to explicitly include fluctuations in collective degrees of freedom into a universal energy density functional method for nuclear structure, their successes, and some remaining open questions.

THE NUCLEAR BORN–OPPENHEIMER METHOD APPLIED TO NUCLEAR COLLECTIVE MOTION

2002 ◽  
Vol 11 (03) ◽  
pp. 231-248
Author(s):  
NOUREDINE ZETTILI ◽  
ABDELKRIM BOUKAHIL
Keyword(s):  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Collective Motion ◽  
Collective Model ◽  
Tensor Operator ◽  
Nbo Method ◽  
Inertial Parameters ◽  
Principal Axes ◽  
Selection Of ◽  
Made In

We deal with the application of the nuclear Born–Oppenheimer (NBO) method to the study of nuclear collective motion. In particular, we look at the description of nuclear rotations and vibrations. The collective operators are specified within the NBO method only to the extent of identifying the type of collective degrees of freedom we intend to describe; the operators are then determined from the dynamics of the system. To separate the collective degrees of freedom into rotational and vibrational terms, we transform the collective tensor operator from the lab fixed frame of reference to the frame defined by the principal axes of the system; this transformation diagonalizes the tensor operator. We derive a general expression for the NBO mean energy and show that it contains internal, collective and coupling terms. Then, we specify the approximations that need to be made in order to establish a connection between Bohr's collective model and the NBO method. We show that Bohr's collective Hamiltonian can be recovered from the NBO Hamiltonian only after adopting some rather crude approximations. In addition, we try to understand, in light of the NBO approach, why Bohr's collective model gives the wrong inertial parameters. We show that this is due to two major reasons: the ad hoc selection of the collective degrees of freedom within the context of Bohr's collective model and the unwarranted neglect of several important terms from the Hamiltonian.

scholarly journals The Prediction of the Electromagnetic Properties and the ?(E2/M1) of 110-116Cd-Isotopes in IBM Model

2011 ◽  
Vol 8 (3) ◽  
pp. 772-780
Author(s):  
Baghdad Science Journal
Keyword(s):  
Nuclear Structure ◽  
The State ◽  
Electromagnetic Properties ◽  
Interacting Boson Model ◽  
Mixing Ratios ◽  
Mixed Symmetry ◽  
Full Symmetry ◽  
Boson Model ◽  
Cd Isotopes ◽  
Spin Contribution

The Nuclear structure of 110-116Cd isotopes was studied theoretically in the framework of the interacting boson model of IBM-l and IBM-2. The properties of the lowest mixed symmetry states such as the 1+, 2+ and 3+ levels produced by the IBM-2 model in the vibrational-limit U(5) of Cd - isotopes are studied in details. This analysis shows that the character of mixed symmetry of 2+ is shared between and states in 110-114Cd – isotopes, the large shar goes to s, while in isotope, the state is declared as a mixed symmetry state without sharing. This identification is confirmed by the percentage of F-spin contribution. The electromagnetic properties of E2 and Ml operators were investigated and the results were analyzed. Various values of eB in the IBM-l and fixed e?= 0.104 eb and e?=0.093 e.b in the IBM-2 are used to generate the B(E2) and Q(2+). Fixed values of g? =0.31?N and g? =-0.31?N were adopted to generate the B(Ml) and ?(E2/ Ml) mixing ratios. The small values of ?(E2/Ml) which obtained for transition from MS- states to those of full symmetry support the conclusion that there may be a strong Ml transition between these states.

scholarly journals Is collective motion symmetric in the neutron‐proton degrees of freedom?

1991 ◽  
Author(s):  
Joseph N. Ginocchio ◽  
Amiram Leviatan ◽  
Michael W. Kirson
Keyword(s):  
Degrees Of Freedom ◽  
Collective Motion

scholarly journals Essentials of the macroscopic-microscopic folded-Yukawa approach and examples of its record in providing nuclear-structure data for simulations

2018 ◽  
Vol 184 ◽  
pp. 01013
Author(s):  
Peter Möller
Keyword(s):  
Nuclear Structure ◽  
Ground State ◽  
Neutron Emission ◽  
Level Structure ◽  
Model Development ◽  
State Level ◽  
Heavy Ion ◽  
Macroscopic Model ◽  
Model Description ◽  
Model Framework

The macroscopic-microscopic model based on the folded-Yukawa singleparticle potential and a “finite-range” macroscopic model is probably the approach that has provided the most reliable predictions of a large number of nuclear-structure properties for all nuclei between the proton and neutron drip lines. I will describe some basic features of the model and the development philosophy that may be the reason for its success. Examples of quantities modeled within the same model framework are, nuclear masses, ground-state level structure, including spins, ground-state shapes, fission barriers, heavy-ion fusion barriers, sub-barrier fusion cross sections, β-decay half-lives and delayed neutron emission probabilities, shape coexistence, and α-decay Qα energies to name a few. I will show how well it predicted various properties measured after published results. Rather than giving an incomplete model description here I will give a timeline of model development and provide references to typical applications and references that are sufficiently complete that several individuals have written computer codes based on these references, codes whose results have excellent agreement with ours.

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