Shape Coexistence in ^{78}Ni as the Portal to the Fifth Island of Inversion
Abstract
Largescale shellmodel calculations predict that the region of deformation which comprises the heaviest chromium and iron isotopes at and beyond N =40 will merge with a new one at N =50 in an astonishing parallel to the N =20 and N =28 case in the neon and magnesium isotopes. We propose a valence space including the full p f shell for the protons and the full s d g shell for the neutrons, which represents a comeback of the the harmonic oscillator shells in the very neutron rich regime. The onset of deformation is understood in the framework of the algebraic SU(3)like structures linked to quadrupole dominance. Our calculations preserve the doubly magic nature of the ground state of ^{78}Ni, which, however, exhibits a welldeformed prolate band at low excitation energy, providing a striking example of shape coexistence far from stability. This new IOI adds to the four welldocumented ones at N =8 , 20, 28, and 40.
 Publication:

Physical Review Letters
 Pub Date:
 December 2016
 DOI:
 10.1103/PhysRevLett.117.272501
 arXiv:
 arXiv:1605.05103
 Bibcode:
 2016PhRvL.117A2501N
 Keywords:

 Nuclear Theory;
 Nuclear Experiment
 EPrint:
 Phys. Rev. Lett. 117, 272501 (2016)