Shape phase transitions in odd-A Zr isotopes

Abstract

Spectroscopic properties that characterize shape phase transitions in neutron-rich odd-A Zr isotopes are investigated using the framework of nuclear density functional theory and particle-core coupling. The interacting-boson Hamiltonian of the even-even core nuclei, and the single-particle energies and occupation probabilities of the unpaired neutron are completely determined by deformation constrained self-consistent mean-field calculations based on the relativistic Hartree-Bogoliubov model with a choice of a universal energy density functional and pairing interaction. The triaxial $(\beta ,\gamma )$ deformation energy surfaces for even-even ${}^{94-102}$Zr indicates transition from triaxial or $\gamma$-soft (${}^{94,96}$Zr) to prolate (${}^{98}$Zr), and triaxial (${}^{100,102}$Zr) shapes. The corresponding low-energy excitation spectra of the odd-A Zr isotopes are in very good agreement with recent experimental results. Consistent with the structural evolution of the neighboring even-even Zr nuclei, the state-dependent effective deformations and their fluctuations in the odd-A isotopes indicate a pronounced discontinuity around the transitional nucleus ${}^{99}$Zr.

Comments: 15 pages, 10 figures, 4 tables