Particle alignments and shape change in ${}^{66}$Ge and ${}^{68}$Ge

Abstract

The structure of the $N\approx Z$ nuclei ${}^{66}$Ge and ${}^{68}$Ge is studied by the shell model on a spherical basis. The calculations with an extended $P+QQ$ Hamiltonian in the configuration space ($2p_{3/2}$, $1f_{5/2}$, $2p_{1/2}$, $1g_{9/2}$) succeed in reproducing experimental energy levels, moments of inertia and $Q$ moments in Ge isotopes. Using the reliable wave functions, this paper investigates particle alignments and nuclear shapes in ${}^{66}$Ge and ${}^{68}$Ge. It is shown that structural changes in the four sequences of the positive- and negative-parity yrast states with even $J$ and odd $J$ are caused by various types of particle alignments in the $g_{9/2}$ orbit. The nuclear shape is investigated by calculating spectroscopic $Q$ moments of the first and second $2^{+}$ states, and moreover the triaxiality is examined by the constrained Hatree-Fock method. The changes of the first band crossing and the nuclear deformation depending on the neutron number are discussed.

18 pages, 21 figures; submitted to Phys. Rev. C

References in corpus (3)

• Shape transition and oblate-prolate coexistence in N=Z fpg-shell nuclei
• Different particle alignments in N \approx Z Ru isotopes studied by the shell model
• Proton-neutron alignment in the yrast states of ${}^{66}$Ge and ${}^{68}$Ge

Cited by in corpus (6)

• Overview of Neutron-Proton Pairing
• Triaxiality and shape coexistence in Germanium isotopes
• Structure of upper g9/2-shell nuclei and shape effect in the 94Ag isomeric states
• Enhancement of $B(E2)$ and low excitation of the second 0${}^{+}$ state near N=40 in Ge isotopes
• Structure of isomeric states in 66As and 67As
• Unique features of structure in an odd-proton $N\approx Z$ nucleus ${}^{69}$As