Nuclear structure properties of $^{184-194}$Pb isotopes and isomers
S. Shukla, P. C. Srivastava
TL;DR
This study applies nuclear-shell-model calculations to $^{184-194}$Pb using the KSHELL code with the KHH7B and KHHE effective interactions to predict energy spectra, electromagnetic properties, and isomeric-state data. The approach emphasizes a valence space with protons below $Z=82$ and neutrons below $N=126$, focusing on how single-particle and collective degrees of freedom interplay near the $^{208}$Pb region, and it analyzes seniority-based configurations to explain isomer decays. Key findings include reasonably good reproduction of negative-parity yrast states, detailed $B(E2)$, $B(M1)$, $Q$, and $oldsymbol{ extmu}$ values, and deformation trends showing $eta_2$ signs that indicate oblate shapes for some isotopes; however, the intruder $0^+_2$ state and several positive-parity states remain challenging, highlighting limitations of the chosen interactions. The results advance understanding of shape coexistence and seniority-driven isomerism in the Pb region and provide predictions and benchmarks for forthcoming experimental measurements in neutron-deficient to mid-shell Pb isotopes, with implications for interpreting nucleosynthesis pathways near $N=126$.
Abstract
In the present work, we study nuclear structure properties of the $^{184-194}$Pb isotopes within the framework of the nuclear shell-model. We have performed shell-model calculations using KHH7B and KHHE interactions. We have reported results for energy spectra, electromagnetic properties such as quadrupole moment ($Q$), magnetic moment ($μ$), $B(E2)$, and $B(M1)$ transition strengths, and compared the shell-model results with the available experimental data. The shell-model results for the half-lives and seniority quantum numbers ($v$) are also reported for the isomeric states.