title: Shape Coexistence in ^{78}Ni as the Portal to the Fifth Island of Inversion.
abstract: Large-scale shell-model 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 pf shell for the protons and the full sdg 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 well-deformed prolate band at low excitation energy, providing a striking example of shape coexistence far from stability. This new IOI adds to the four well-documented ones at N=8, 20, 28, and 40.
authors.affiliation: Université de Strasbourg, IPHC, 23 rue du Loess 67037 Strasbourg, France.|CNRS, UMR7178, 67037 Strasbourg, France.
authors.forename: F
authors.initials: F
authors.lastname: Nowacki
authors.affiliation: Departamento de Física Teórica e IFT-UAM/CSIC, Universidad Autónoma de Madrid, E-28049 Madrid, Spain and Institute for Advanced Study, Université de Strasbourg, France.
authors.forename: A
authors.initials: A
authors.lastname: Poves
authors.affiliation: Université de Strasbourg, IPHC, 23 rue du Loess 67037 Strasbourg, France.|CNRS, UMR7178, 67037 Strasbourg, France.
authors.forename: E
authors.initials: E
authors.lastname: Caurier
authors.affiliation: Université de Strasbourg, IPHC, 23 rue du Loess 67037 Strasbourg, France.|CNRS, UMR7178, 67037 Strasbourg, France.
authors.forename: B
authors.initials: B
authors.lastname: Bounthong