Simultaneous description of low-lying positive and negative parity bands in heavy even-even nuclei

Abstract

The low-lying spectra including the first few excited positive and negative parity bands of some heavy even-even nuclei from the rare earth and actinide mass regions are investigated within the framework of the symplectic Interacting Vector Boson Model with Sp(12,R) dynamical symmetry group. Symplectic dynamical symmetries allow the change of the number of excitation quanta or phonons building the collective states providing for larger representation spaces and richer subalgebraic structures to incorporate more complex nuclear spectra. The theoretical predictions for the energy levels and the electromagnetic transitions between the collective states of the ground state band and K π = 0 − band are compared with experiment and some other collective models incorporating octupole and/or dipole degrees of freedom. The energy staggering which is a sensitive indicator of the octupole correlations in the even-even nuclei is also calculated and compared with experiment. The results obtained for the energy levels, energy staggering and transition strengths reveal the relevance of the used dynamical symmetry of the model for the simultaneous description of both positive and negative parity low-lying collective bands.

Coexistence and fluctuations phenomena with Davidson-like potentials in quadrupole–octupole deformed nuclei

“…A diversity of methods and techniques were utilized to study the role of the octupole degree of freedom. These include density functional models [21][22][23], interacting boson and boson vector models [24,25], and collective models, such as the coherent quadrupole-octupole model (CQOM) [26,27].…”

Isospin excitation and shape phase transition in odd-mass Cu isotopes

“…7, but this model is related to a description of even-even nuclei. Recently, exact solutions of the solvable Hamiltonian regarding the extension of IBM using the vector boson, 8,9 IBM-2 10 and the IBFM 11 were obtained. The study of the lighter nucleus (N Z nuclei) is an interesting and important subject.…”

Descriptive study of the even-even actinide nuclei 230 − 234 Th isotopes using IBM-1

“…The properties of excited nuclear states, such as excitation energy, spin and parity, and electromagnetic transitions probabilities, are determined by the intrinsic, underlying shape or deformation of the nuclear mean field and its (proton) charge distribution [5]. It is particularly important to analyse the structure of heavy actinide nuclei where the quadrupole deformation is well established and noted [6][7][8][9][10].…”