Experimental $B\left(E2\right)$ reduced transition strengths in $N=50$, 126 and $Z=82$ semimagic nuclei are compared to the values predicted by the seniority scheme for a single $j=9/2$ orbital. For the first time all available data, both on even- and odd-mass nuclei, were considered in the same framework. The seniority scheme provides a good approximation for all these three regions with the best fit given by the lead isotopes. In addition, shell model calculations using well-established interactions were performed. In the $N=50$ and $Z=82$ nuclei considering all orbitals within a shell provide only a limited improvement in reproducing the data when compared to the seniority scheme. In contrast, the shell model provides much better agreement for $N=126$ nuclei, where the $\pi f_{7/2}$ orbital has increasing effect on the transition strengths as the $j=9/2$ orbital is filled. In order to further test the applicability of the seniority scheme in the lead isotopes, and investigate the possible distorting effect of the $\nu i_{11/2}$ orbital, more experimental information is required, especially for ${}^{214,215,216}\mathrm{Pb}$.

Close

PrevNext

View figure in article

• Electromagnetic transitions
• Nuclear structure & decays
• Shell model