Shell model study ofT=0states forCd96by the nucleon-pair approximation

Abstract

In this paper we study the nucleon-pair approximation for $T=0$ states of $^{96}\mathrm{Cd}$ in the $1{p}_{1/2}1{p}_{3/2}0{f}_{5/2}0{g}_{9/2}$ shell with the JUN45 interaction. The lowest seniority scheme and the isoscalar spin-one pair approximation are not enough to describe the states. The isoscalar spin-aligned pair approximation is reasonably good for the yrast ${2}^{+}, {4}^{+}, {6}^{+}, {12}^{+}, {14}^{+}$, and ${16}^{+}$ states as pointed out previously. Not only the yrast positive-parity states but also nonyrast states and negative-parity states are well described by both the isovector pair approximation and the isoscalar pair approximation. We calculate overlaps between nucleon-pair basis states and shell-model wave functions. The largest overlaps and the corresponding nucleon-pair basis states are presented. We find that isovector spin-zero pairs, isovector spin-two pairs, and isoscalar spin-aligned pairs are the dominant building blocks in these states.