| Irfu-11-94
|
|---|
| First spectroscopy of 66Se and 65As: investigating shape coexistence beyond
the N = Z line. |
| A. Obertelli et al (S. Boissinot, F. Flavigny, W. Korten, J. Ljungvall, B. Sulignano)
|
| We report on the rst
spectroscopy of 66Se and 65As from two-neutron removal at intermediate beam
energies. The deduced excitation energies for the rst-excited states in 66Se and 65As are compared to
mean- eld-based predictions within a collective Hamiltonian formalism using the Gogny D1S e ective
interaction and to state-of-the-art shell-model calculations restricted to the pf5=2g9=2 valence space.
The obtained Coulomb-energy di erences for the rst excited states in 66Se and 65As are discussed
within the shell-model formalism to assess the shape-coexistence picture for both nuclei. Our results
support a favored oblate ground-state deformation in 66Se and 65As. A shape transition for the ground
state of even-odd As isotopes from oblate in 65As to prolate in 67;69;71As is suggested. |
