Estimation of 
M1
 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

The structure of the Ζ,Ν < 50 nuclei is examined in a model space consisting of the 0g9/2, 1p1/2, 1p3/2 and the 0f5/2 hole orbitals outside the doubly closed 100Sn core. The effective interaction for this model space is derived by introducing second order corrections to the Sussex matrix elements, while the one-hole energies are deduced by a least square fit to the observed levels. The results of the calculation are found to be in very satisfactory agreement with experiment for all nuclei with 38<Ζ<46 but for Ζ<38 this agreement begins to deteriorate. Such a feature possibly indicates the appearance of deformation and the breaking of the Ν=50 core. The wavefunctions of the calculation are used to determine double β matrix elements in the Ge, Se, Sr and Kr isotopes.

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SUPER-ASYMMETRIC COLD FISSION AND EXOTIC CLUSTER-DECAY

International Journal of Modern Physics E ◽

10.1142/s0218301394000085 ◽

1994 ◽

Vol 03 (01) ◽

pp. 195-218 ◽

Cited By ~ 20

Author(s):

SATISH KUMAR ◽

RAJ K. GUPTA ◽

WERNER SCHEID

Keyword(s):

Experimental Data ◽

Mass Region ◽

Cluster Decay ◽

Model Calculations ◽

Decay Modes ◽

Cluster Radioactivity ◽

Decay Products ◽

Text Fragment ◽

Mechanical Fragmentation ◽

Cold Fission

Cold fission of radioactive nuclei is studied in the super-asymmetric mass region of exotic cluster radioactivity, using the quantum-mechanical fragmentation theory (QMFT) based saddle-point fission (SPF) model for calculating the decay half-life times. The calculations show that cold fission also prefers light fragments like 24–26Ne, 28,30Mg, 32,34,36Si, 37P 38S, 46Ar and 48,50Ca, some of which are observed in exotic cluster radioactivity. The predictions of the SPF model calculations are compared with the available exotic cluster-decay experimental data and the calculations based on the preformed-cluster model (PCM). The SPF model calculations show large disagreements with both the PCM and cluster-decay experimental data. For clusters of mass A2<46, the predicted half-lives for the SPF model are much smaller than for the PCM, which apparently means predicting the cold fission as a more probable process than the cluster-decay. The cold fission predicts some new decay modes which are far more probable (smaller log10 T1/2-values) as cold fission fragments than as cluster-decay products. For heavier clusters (A2≥46), the two models (SPF and PCM) make nearly identical predictions, which means predicting an overlap of two processes (cold fission and cluster-decay) for A2>46. Also, cold fission is found to be more probable than hot fission and a new fission mode (known as bimodel fission) is identified in the neighbourhood of the doubly magic [Formula: see text] fragment. Our calculations are made for 234U, 238Pu, 241Am and 252Cf.

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Simple Model Calculations of Spin and Quantized Alignment for the

Acta Physica Hungarica ◽

10.1556/aph.25.2006.1.11 ◽

2006 ◽

Vol 25 (1) ◽

pp. 117-134 ◽

Cited By ~ 5

Author(s):

A.S. Shalaby ◽

A.S. Shalaby

Keyword(s):

Simple Model ◽

Mass Region ◽

Model Calculations

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Level spacing distribution of scissors mode states in heavy deformed nuclei

Physics Letters B ◽

10.1016/s0370-2693(00)00779-6 ◽

2000 ◽

Vol 486 (3-4) ◽

pp. 273-278 ◽

Cited By ~ 32

Author(s):

J. Enders ◽

T. Guhr ◽

N. Huxel ◽

P. von Neumann-Cosel ◽

C. Rangacharyulu ◽

...

Keyword(s):

Level Spacing ◽

Deformed Nuclei ◽

Spacing Distribution ◽

Scissors Mode ◽

Level Spacing Distribution

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ON THE SEARCH FOR THE SCISSORS MODE

Modern Physics Letters A ◽

10.1142/s0217732393002658 ◽

1993 ◽

Vol 08 (13) ◽

pp. 1171-1178 ◽

Cited By ~ 3

Author(s):

ROLAND NOJAROV ◽

AMAND FAESSLER

Keyword(s):

Wave Function ◽

Form Factor ◽

Form Factors ◽

Transition Density ◽

Light Nuclei ◽

Heavy Nuclei ◽

Deformed Nuclei ◽

Scissors Mode ◽

Transition Densities ◽

Rotor Model

Results from quasiparticle RPA calculations on 1+ excitations in deformed nuclei, including M1 transition densities and (e, e′) form factors, are compared to the microscopic representation of the scissors state of the two-rotor model. Although this state is too collective, especially in heavy nuclei, it fragments mainly over the low lying orbital M1 excitations, which can be interpreted as a manifestation of a weakly collective scissors mode. The experimentally observed strongest M1 excitation has the same leading components in the wave function as the scissors state, the largest overlap with it, and similar transition density and form factor. Although the scissors mode is more pronounced in heavy deformed nuclei, the strong low lying orbital M1 excitations in lighter nuclei represent a better approximation to it, because the scissors state is less collective in light nuclei.

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Shell model calculations in the A ~ 100 mass region

HNPS Proceedings ◽

10.12681/hnps.2931 ◽

2020 ◽

Vol 6 ◽

pp. 225

Author(s):

P. Divari ◽

L. D. Skouras

Keyword(s):

Shell Model ◽

Large Scale ◽

Model Space ◽

Mass Region ◽

Matrix Elements ◽

Model Calculations ◽

Single Neutron ◽

Least Squares Fit ◽

The Matrix ◽

Inert Core

The properties of nuclei with 39≤Ζ≤47 and Ν=51-52 are investigated in large scale shell-model calculations. The doubly closed nucleus 100Sn is selected as the reference state and the nuclei under examination are described in terms of proton holes and one up two neutrons outside the inert core. The proton holes are distributed in a model space consisting of the orbitals g9/2, p1/2, p3/2 while f5/2 is sometimes also considerd. Similary the model space for the neutron particles in cludes the orbitals g7/2, d5/2, d3/2, s1/2 and in certain cases h11/2. The effective two-body interaction and the matrix elements of the effective operators were deter mined by introducing second-order corrections to the Sussex matrix elements. The single proton holes as well as the single-neutron energies were treated as parameters which were determined by least-squares fit to the observed levels of 39≤Ζ≤47, Ν=50 and Ν=51 respectively. The results of the calculation were found to be in satisfactory agreement with experimental data and this enable us to make predictions about the properties of some exotic nuclei in the vicinity of 100Sn.

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