SHAPE COEXISTENCE AND SUPERDEFORMATION IN28Si

Abstract

We study the shape coexistence of differently deformed states within 28Si using shell-model and beyond-mean-field techniques. Experimentally, 28Si exhibits shape coexistence between an oblate ground state and an excited prolate structure. The oblate rotational band is described well within the sd shell using the USDB interaction. However, for the prolate band, a modification of this interaction is required, lowering the single-particle energy of the 1d3/2 orbit. Furthermore, we explore the possibility of a superdeformed configuration in 28Si. Our calculations, spanning both the sd and pf shells, rule out the existence of a superdeformed 0+ bandhead within an excitation energy range of 10-20 MeV.