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Magnetic dipole excitations in even-even nuclei

Magnusson, Charlotte LU orcid (1991)
Abstract
The properties of K(pi) = 1+ states in deformed even-even rare-earth nuclei have been investigated within the Quasiparticle Random Phase Approximation (QRPA). The B(M1) spectrum and the differential cross section for electron scattering have been calculated and are seen to be consistent with the interpretation that the experimental 1+ states first considered to be a scissors mode, actually correspond to slightly collective states with the main proton components coming from positive parity proton states. The effect of the presence of quadruple pairing on these states is also investigated, and it is seen that a (lambda, mu) = (2, +-1) quadrupole pair interaction will increase the B(M1) strength found at the low energy side of the spectrum.... (More)
The properties of K(pi) = 1+ states in deformed even-even rare-earth nuclei have been investigated within the Quasiparticle Random Phase Approximation (QRPA). The B(M1) spectrum and the differential cross section for electron scattering have been calculated and are seen to be consistent with the interpretation that the experimental 1+ states first considered to be a scissors mode, actually correspond to slightly collective states with the main proton components coming from positive parity proton states. The effect of the presence of quadruple pairing on these states is also investigated, and it is seen that a (lambda, mu) = (2, +-1) quadrupole pair interaction will increase the B(M1) strength found at the low energy side of the spectrum. No sign of such an increase is yet seen experimentally. The effect of nuclear deformation on the B(M1) spectrum is also investigated. A schematic model indicates a seemingly quadratic deformation dependence of the summed B(M1) strength. The same type of deformation dependence is obtained in a more realistic model and the results in a sequence of Samarium isotopes are seen to be in qualitative agreement with the experimentally obtained data. (Less)
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author
supervisor
opponent
  • unknown], [unknown
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Fysicumarkivet A:1991:Magnusson
pages
52 pages
defense location
Fysiska Institutionens föreläsningssal
defense date
1991-05-31 10:15:00
language
English
LU publication?
yes
id
16135b17-88a8-4c5f-bda0-afc3352ece17 (old id 2536301)
date added to LUP
2016-04-04 14:27:47
date last changed
2023-03-17 12:08:14
@phdthesis{16135b17-88a8-4c5f-bda0-afc3352ece17,
  abstract     = {{The properties of K(pi) = 1+ states in deformed even-even rare-earth nuclei have been investigated within the Quasiparticle Random Phase Approximation (QRPA). The B(M1) spectrum and the differential cross section for electron scattering have been calculated and are seen to be consistent with the interpretation that the experimental 1+ states first considered to be a scissors mode, actually correspond to slightly collective states with the main proton components coming from positive parity proton states. The effect of the presence of quadruple pairing on these states is also investigated, and it is seen that a (lambda, mu) = (2, +-1) quadrupole pair interaction will increase the B(M1) strength found at the low energy side of the spectrum. No sign of such an increase is yet seen experimentally. The effect of nuclear deformation on the B(M1) spectrum is also investigated. A schematic model indicates a seemingly quadratic deformation dependence of the summed B(M1) strength. The same type of deformation dependence is obtained in a more realistic model and the results in a sequence of Samarium isotopes are seen to be in qualitative agreement with the experimentally obtained data.}},
  author       = {{Magnusson, Charlotte}},
  keywords     = {{Fysicumarkivet A:1991:Magnusson}},
  language     = {{eng}},
  school       = {{Lund University}},
  title        = {{Magnetic dipole excitations in even-even nuclei}},
  year         = {{1991}},
}