Mixed Symmetry States in 92Zr and 94Mo Nuclei

Mixed-symmetry states of 92Zr and 94Mo isotopes are investigated with the use of the collective models, Interacting Boson Model-2 (IBM-2) and Quasiparticle Phonon Model (QPM). The energy spectra and electromagnetic transition rates for these isotopes are calculated. The results of IBM-2 and QPM are compared with available experimental data. We have obtained a satisfactory agreement, and IBM-2 gives a better description. In these isotopes, we observe a few states having a mixed symmetry such as 2+2, 2+3, 3+1, and 1+s. It is found that these isotopes have a vibrational shape corresponding to the U(5) symmetry.

Shape coexistence in $^{76}$Se within the neutron-proton interacting boson model

We have investigated the low-lying energy spectrum and electromagnetic transition strengths in even-even $^{76}$Se using the proton-neutron interacting boson model (IBM-2). The theoretical calculation for the energy levels and $E2$ and $M1$ transition strengths is in good agreement with the experimental data. Especially, the excitation energy and $E2$ transition of $0^+_2$ state, which is intimately associated with shape coexistence, can be well reproduced. The analysis on low-lying states and some key structure indicators indicates that there is a coexistence between spherical shape and $\gamma$-soft shape in $^{76}$Se.

Configuration Mixing for Po Isotopes within the Interacting Boson Model-2

We analyze a sequence of 194−204Po isotopes, using the Configuration Mixing (CM) Interacting Boson Model 2 (IBM-2). We set the parameters of Hamiltonian using a least-square fit for the known energy levels, electrical transition rates B(E2), and quadruple moments Q(2+1) for the first excited states. We have a good agreement with the experimental values for all the observables tested, and we infer that the feature of the shape coexistence is concealed in the isotopes of Po, just as in the isotopes of Os and Pt.

Nuclear Gamma-soft Character in ¹²⁸Ba

We report the properties of gamma soft O(6) of 128Ba isotones with neutron N = 72 using Interacting Vector Boson Model (IVBM), interacting Boson Model (IBM-1), Bohr-Mottelson Model (BM), and Doma-El-Gendy (D-G) relation. The first energy level ( ) and ratio have been investigated which show that 128Ba has gamma-soft character. The curves Eγ/Vs.J of E-GOS of even 128Ba nucleus were compared with the standard curves of vibrational, gamma soft and rotational limits. The staggering factors were studied of available measured data of 128Ba nucleus. The yrast levels of this isotope are calculated by the model of VBMI, IBM-1, BM and D-G and they were compared by measured data. The negative parity band of 128Ba was calculated by IVBM and BM model and compared with experimental values.

Investigation of Proton and Neutron Alignment in the Ba and Ce Isotopes within Interaction Interacting Boson Model and Triaxial Rotor Model

In the form of two quasi-particles coupled to a core described by the IBM-1 and Triaxil Rotor models, the high-spin states of the Ba and Ce isotopes are studied. Bands based on both (vh11/2)-2 and (configurations are considered, which is found to be appropriate for this region to better explain band-crossing systems. Between the recent experimental data and the calculated energy spectra and electric transition probability, fair agreement is achieved.