Reexamining the nuclear structure of ${}^{154}\mathrm{Gd}$ in the dynamic pairing plus quadrupole model

In a previous study of the collective multiphonon bands in ${}^{154}\mathrm{Gd}$, using the microscopic dynamic pairing plus quadrupole model, data for eight $K$ bands were analyzed. In the last four decades, its decay scheme is significantly revised and the nuclear theory has undergone a significant change. Special focus is on new weak intensity transitions in several bands and on the reassigned levels in its decay scheme. The present study represents a detailed revised analysis of the collective even parity bands below 2.1 MeV. Also, a discussion is given on the nature of the $K^{\pi }=0^{+}$ excited bands, validity of band mixing approach, and of the assumption of shape coexistence of β band with ground band. Comparison is made with the $X$(5) analytical symmetry and the algebraic interacting boson model predictions. Discussion of the $2n$ transfer reactions is given. The validity of the multiphonon view of the $K^{\pi }=4^{+}$ and $2_2^{+}$ bands is also studied.

Figure 1

(a) The partial energy level spectrum in ${}^{154}\mathrm{Gd}$ [13]. (b) The partial energy level spectrum in ${}^{154}\mathrm{Gd}$ from DPPQ model.

Figure 2

$N=90$ energy levels. The $K^{\pi }=0_2^{+}$ bands are well visible. $2_3=2_{\gamma }$ lies above $2_2=2_{\beta }$.

Figure 3

The energy difference $E(2_{\beta }-0_{\beta })$ versus $E\left(2_{\mathrm{g}}\right)$ for Ba-Dy $(N=88-96)$.The continuous line is the diagonal.

Figure 4

The potential energy curve $V(\beta ,\gamma =0^{\circ })$ in ${}^{154}\mathrm{Gd}$ from DPPQM. ZPE denotes the zero point energy $\sim 1.8\mathrm{MeV}$ above the $V_{min}$.