Description of nuclear octupole and quadrupole deformation close to the axial symmetry and phase transitions in the octupole mode

Abstract

The dynamics of nuclear collective motion is investigated in the case of reflection-asymmetric shapes. The model is based on a new parameterization of the octupole and quadrupole degrees of freedom, valid for nuclei close to the axial symmetry. Amplitudes of oscillation in other degrees of freedom different from the axial ones are assumed to be small, but not frozen to zero. The case of nuclei which already possess a permanent quadrupole deformation is discussed in some more detail and a simple solution is obtained at the critical point of the phase transition between harmonic octupole oscillation and a permanent asymmetric shape. The results are compared with experimental data of the Thorium isotopic chain. The isotope Th-226 is found to be close to the critical point.

17 pages, 5 figures, 8 tables; 3 new references added, misprints corrected

References in corpus (3)

• A test of X(5) for the gamma degree of freedom
• Consequences of wall stiffness for a beta-soft potential
• E(5) and X(5) critical point symmetries obtained from Davidson potentials through a variational procedure

Cited by in corpus (24)

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• Microscopic core-quasiparticle coupling model for spectroscopy of odd-mass nuclei with octupole correlations
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