Shape coexistence inBa132

Abstract

Rotational states have been populated in y-soft " Ba following the ' Sn("C,3ny) reaction. The ground state of this nucleus is predicted to possess maximal triaxiality y --30 . Two hI =2 bands were established, based on quasineutron configurations with large negative y deformations close to the collective oblate shape y= -60'. The bandhead of one of these bands, associated with a [vh»z~] configuration, was found to be isomeric with a mean lifetime &=12. 5+0.3 ns. A third EI=2 band was observed, built on a two-quasiproton configuration with a near-prolate shape (y -0 ). In addition, two AI = 1 bands, built on mixed proton-neutron four-quasiparticle configurations with oblate shapes (y --60 ), were established.

Quadrupole moments of 7−, 9/2− and 23/2+ isomeric states in 128Ba and 129Ba

“…The different deformation-driving properties of neutrons and protons occupying the unique parity subshell h 11/2 in the high-Ω and low-Ω orbitals, respectively, lead to the occurrence of shape coexistence and thus to triaxial shapes [2,3]. The γ-degree of freedom was found to play an important role in the description of these nuclei [4]. A large triaxiality within the range 20 o − 30 o [5] has been established for the even-even Xe, Ba and Ce nuclei from the analysis of the low-lying state properties within the rigidtriaxial rotor model [6,7] and the interacting boson model [8,9].…”

Energy spectra and E2 transition rates of 124—130Ba

“…algebraic technique and explores the properties of nuclei have classified in the U(5)↔SO (6) transitional region of IBM.…”

“…When the numbers of protons (or neutrons) are modified, the energy levels and electromagnetic transition rates of atomic nuclei change too and suggest a transition from one kind of the collective behavior to another [1][2][3]. The quantum shape phase transitions have been studied 25 years ago with using the classical limits of the Interacting Boson Model (IBM) [4][5][6][7][8][9][10] which describes the nuclear structure of even-even nuclei within the U(6) symmetry, possessing U(5), SU (3) and O(6) dynamical symmetry limits, These descriptions point out that there is a first order shape phase transition between U(5) and SU (3)limits and a second order shape phase transition between U(5) and O (6) limits. The analytic description of nuclear structure at the critical point of phase transitions has attracted extensive interest in the recent decades.…”

Theoretical Description of energy spectra and Quadrupole transition probabilities 0f 192 Pt

“…These mean 192 Pt isotope appear to evolve from the O(6) to U(5)-like structure in IBM classification. On the other hand, this isotope can be described via O (6) limit where one has to use S80 the U(5) limit predictions for the intruder states. These levels [15].…”

“…The model present three special limits that can be solved easily these three limits are U (5), SU (3) and O (6) dynamical symmetry appropriate for an harmonic vibrator , axial deformed rotor and γ-unstable deformed rotor .When the numbers of protons (or neutrons) are modified, the energy levels and electromagnetic transition rates of atomic nuclei change too and suggest a transition from one kind of the collective behavior to another [1][2][3]. The quantum shape phase transitions have been studied 25 years ago with using the classical limits of the Interacting Boson Model (IBM) [4][5][6][7][8][9][10] These descriptions point out that there is a first order shape phase transition between U(5) and SU(3)limits and a second order shape phase transition between U(5) and O(6) limits. The analytic description of nuclear structure at the critical point of phase transitions has attracted extensive interest in the recent decades.…”