Interference between spherical and deformed states in ¹⁹⁰Pb

Abstract

The level scheme of ¹⁹⁰Pb identified in the ¹⁶⁶Er(²⁸Si,4n)¹⁹⁰Pb reaction includes several long isomers and exhibits structures which can be associated with co-existing spherical, oblate and prolate configurations. A chance near-degeneracy between 8⁺ states from the competing configurations causes mixing and fragmentation of the observed E3 and E2 decays from the yrast 11⁻ and 10⁺ states, through interference. The candidate identified for the prolate band is approximately 500 keV higher than that observed in ¹⁸⁸Pb.