Nuclear structure of 96,98Mo: Shape coexistence and mixed-symmetry states

Abstract

Excited low-spin states in 96 Mo and 98 Mo have been studied in γγ angular correlation experiments in order to determine spins and multipole mixing ratios. Furthermore, from a Doppler lineshape analysis effective lifetimes τ in the femtosecond range were obtained. The experimental data show a complex spectrum due to configuration mixing, which is confirmed by Interacting Boson Model calculations based on a Skyrme energy density functional. The M 1-transition strengths of transitions depopulating excited 2 + states to the first 2 + state are discussed in terms of the proton-neutron mixed symmetry.

Bohr Hamiltonian with an energy-dependent $\gamma$ γ -unstable Coulomb-like potential

“…In consequence, the structure of the shape coexistence in 72 Se is well estab- lished as having near spherical and prolate components [38,71]. A similar interpretation is also proposed for 98 Mo [39,40,44] with a mixture between spherical and γ-soft equilibrium shapes. Alternatively, a description through coexistence of various triaxial shapes [70] was also offered for this nucleus.…”

“…Although the theoretical description of the phenomenon is usually approached with deformed mean-field models or shell-model calculations using different effective interactions extensively reviewed in Ref. [37] and more recently with interacting boson model based approaches [38][39][40][41][42][43][44][45], the interpretation of the resulting low lying energy spectrum is often made with the aid of a collective wave-function or by mappings in collective coordinates. Therefore, a fully collective description of these 0 + states is more than justified.…”

Shell evolution of stable N = 50-56 Zr and Mo nuclei with respect to low-lying octupole excitations

“…In order to test the simple approach used here, the 4 [19]. The data for the 1 + levels were taken from refs.…”

“…1(d)). For several of the nuclei under consideration the structures built upon this low-lying 0 + level have been shown to possess an enhanced quadrupole collectivity [17][18][19][20].…”

Global analysis of quadrupole shape invariants based on covariant energy density functionals

“…These changes occur because of the crossing between coexisting structures, that is, highly-deformed prolate and spherical configurations [1]. Numerous measurements of spectroscopic quadrupole moments, B(E2) values, E0 transitions, two-nucleon and α-cluster transfer data, have revealed the onset of shape coexistence in Sr, Zr, and Mo isotopes [1,[35][36][37][38][39][40][41][42][43], while static and dynamic quadrupole moments data show that shape coexistence still persists in Ru and Pd isotopes [1,10,[44][45][46]. Our calculation also indicates that heavier Ru and Pd isotopes exhibit shape coexisting structures, with triaxiality playing an important role [46,47].…”