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Microscopic Properties of Superdeformed Nuclei

Karlsson, Lennart B LU (1999)
Abstract
Many high spin rotational bands in superdeformed nuclei have been found in the <i>A ~ 140-150</i> region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed shapes. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy.



Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with... (More)
Many high spin rotational bands in superdeformed nuclei have been found in the <i>A ~ 140-150</i> region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed shapes. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy.



Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential.



In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the <i>E<sub>gamma</sub></i> and <i>J<sup>(2)</sup></i> distributions. The importance of high-<i>N</i> orbitals for identical bands is also discussed.



Additivity of electric quadrupole moment contributions in the superdeformed <i>A ~ 150</i> region is discussed with the nucleus <sup>152</sup>Dy as a core. In analytic harmonic oscillator calculations, the effective electric quadrupole moment <i>q<sub>eff</sub></i>, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass quadrupole moment <i>q<sub>v</sub></i>. Also in realistic calculations, simple relations between <i>q<sub>eff</sub></i> and <i>q<sub>v</sub></i> can be used to estimate the total electric quadrupole moment, e.g. for the nucleus <sup>142</sup>Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of <sup>152</sup>Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed <i>A ~ 150</i> region.



For the superdeformed region around <sup>143</sup>Eu, configuration and spin assignments are made based on effective alignments. The region is connected to, and compared with, previously investigated <sup>146-153</sup>Gd nuclei. The two regions show similarities but it appears difficult to get consistent alignments in the whole region around <sup>143</sup>Eu. (Less)
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author
opponent
  • Professor Dobaczewski, Jacek, Warsaw University, Polen
organization
publishing date
type
Thesis
publication status
published
subject
keywords
statistical physics, gravitation, superdeformation, Nilsson-Strutinsky, modified oscillator potential, moments of inertia, transition energies, rotational bands, quadrupole moments, spin assignments, identical bands, additivity., Mathematical and general theoretical physics, classical mechanics, relativity, quantum mechanics, kvantmekanik, klassisk mekanik, thermodynamics, Matematisk och allmän teoretisk fysik, termodynamik, relativitet, statistisk fysik, Fysicumarkivet A:1999:Karlsson
pages
102 pages
publisher
Mathematical Physics, Lund Institute of Technology, Lund University
defense location
Lecture hall B, Department of Physics
defense date
1999-05-28 10:15
external identifiers
  • other:ISRN: Lund-MPh-99/03
ISBN
91-628-3561-0
language
English
LU publication?
yes
id
68c7d26a-0b3d-4390-8ab4-c6ce58112e71 (old id 39737)
date added to LUP
2007-08-01 12:31:40
date last changed
2016-09-19 08:45:03
@phdthesis{68c7d26a-0b3d-4390-8ab4-c6ce58112e71,
  abstract     = {Many high spin rotational bands in superdeformed nuclei have been found in the &lt;i&gt;A ~ 140-150&lt;/i&gt; region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed shapes. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy.<br/><br>
<br/><br>
Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential.<br/><br>
<br/><br>
In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the &lt;i&gt;E&lt;sub&gt;gamma&lt;/sub&gt;&lt;/i&gt; and &lt;i&gt;J&lt;sup&gt;(2)&lt;/sup&gt;&lt;/i&gt; distributions. The importance of high-&lt;i&gt;N&lt;/i&gt; orbitals for identical bands is also discussed.<br/><br>
<br/><br>
Additivity of electric quadrupole moment contributions in the superdeformed &lt;i&gt;A ~ 150&lt;/i&gt; region is discussed with the nucleus &lt;sup&gt;152&lt;/sup&gt;Dy as a core. In analytic harmonic oscillator calculations, the effective electric quadrupole moment &lt;i&gt;q&lt;sub&gt;eff&lt;/sub&gt;&lt;/i&gt;, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass quadrupole moment &lt;i&gt;q&lt;sub&gt;v&lt;/sub&gt;&lt;/i&gt;. Also in realistic calculations, simple relations between &lt;i&gt;q&lt;sub&gt;eff&lt;/sub&gt;&lt;/i&gt; and &lt;i&gt;q&lt;sub&gt;v&lt;/sub&gt;&lt;/i&gt; can be used to estimate the total electric quadrupole moment, e.g. for the nucleus &lt;sup&gt;142&lt;/sup&gt;Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of &lt;sup&gt;152&lt;/sup&gt;Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed &lt;i&gt;A ~ 150&lt;/i&gt; region.<br/><br>
<br/><br>
For the superdeformed region around &lt;sup&gt;143&lt;/sup&gt;Eu, configuration and spin assignments are made based on effective alignments. The region is connected to, and compared with, previously investigated &lt;sup&gt;146-153&lt;/sup&gt;Gd nuclei. The two regions show similarities but it appears difficult to get consistent alignments in the whole region around &lt;sup&gt;143&lt;/sup&gt;Eu.},
  author       = {Karlsson, Lennart B},
  isbn         = {91-628-3561-0},
  keyword      = {statistical physics,gravitation,superdeformation,Nilsson-Strutinsky,modified oscillator potential,moments of inertia,transition energies,rotational bands,quadrupole moments,spin assignments,identical bands,additivity.,Mathematical and general theoretical physics,classical mechanics,relativity,quantum mechanics,kvantmekanik,klassisk mekanik,thermodynamics,Matematisk och allmän teoretisk fysik,termodynamik,relativitet,statistisk fysik,Fysicumarkivet A:1999:Karlsson},
  language     = {eng},
  pages        = {102},
  publisher    = {Mathematical Physics, Lund Institute of Technology, Lund University},
  school       = {Lund University},
  title        = {Microscopic Properties of Superdeformed Nuclei},
  year         = {1999},
}