Shell Model Study of the Neutron-Rich Nuclei around N=28

Abstract

We describe the properties of the neutron rich nuclei around N=28 in the shell mode framework. The valence space comprises the $sd$ shell for protons an the $pf$ shell for neutrons without any restriction. Good agreement is found with the available experimental data. The N=28 shell closure, even if eroded due to the large neutron excess, persists. The calculations predict that ${}^{40}$S and ${}^{42}$S are deformed with $\beta =0.29$ and $\beta =0.32$ respectively.

Comments: 17 pages and 19 figures, LateX, RevTeX