Many-particle many-hole states near the magic number 20: deformed and superdeformed states

Abstract

Many-particle many-hole states near the magic number 20 have been investigated in the relativistic mean field formalism using the fixed configuration method. Neutron particle-hole states in neutron-rich nuclei with $N\sim 20$, {\em i.e.} ${}^{30,32,34}$Mg,and ${}^{28,30}$Ne are studied to find out the ground state configuration. The ground state of ${}^{32}$Ne,Mg as well as possibly ${}^{34}$Mg comes out actually as particle-hole states. Proton-neutron excitation across the shell gap at 20 in nuclei with $N=Z$, {\em i.e.} ${}^{32}$S, ${}^{36}$Ar, ${}^{40}$Ca and ${}^{44}$Ti is investigated as possible origins of superdeformed configuration. Observed superdeformed bands in ${}^{36}$Ar and ${}^{40}$Ca can be described as many-particle many-hole states.

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