Variational Approach to Coexistence Phenomena in N=Z Nuclei

Abstract

Results are presented concerning shape coexistence and neutron-proton correlations at low and high spins in the N = Z nuclei ⁶⁸ Se and ⁵⁶ Ni obtained within the complex version of the Excited Vampir variational approach using a rather large model space and realistic effective interactions. Oblate-prolate coexistence at low and intermediate spins dominates the structure of the nucleus ⁶⁸ Se. The coexistence of small and moderately deformed oblate and prolate configurations, strongly mixed in some cases, may explain the irregularities observed for the yrast line, as well as the presence of other nonyrast states in the nucleus ⁵⁶ Ni. The first deformed band is well reproduced and predictions on the structure of the next deformed bands are presented.