Partial conservation of seniority and its unexpected influence on E2 transitions in $g_{9/2}$ nuclei

TL;DR

This paper explores how partial seniority conservation influences E2 transitions in $g_{9/2}$ nuclei, revealing that configuration mixing significantly affects transition properties and explains experimental observations.

Contribution

It demonstrates the role of partial seniority conservation and configuration mixing in understanding E2 transitions in $g_{9/2}$ nuclei, including the impact of cross-orbital interactions.

Findings

Partial seniority conservation affects E2 transition properties.

Configuration mixing explains observed transition behaviors.

Strong mixing between v=2 and v=4 states is induced by non-diagonal interactions.

Abstract

There exist two uniquely defined $v=4$ states in systems within a $j=9/2$ subshell, which automatically conserve seniority and do not mix with other states. Here I show that the partial conservation of seniority plays an essential role in our understanding of the electric quadrupole transitions of the semimagic nuclei involving $j=9/2$ subshells, including the long-lived $8^{+}$ isomer in $^{94}$Ru. The effects of configuration mixing from neighboring subshells on the structure of those unique states are analysed. It is shown that a sharp transition from pure seniority coupling to a significant mixture between the $v=2$ and $v=4$ states may be induced by the cross-orbital non-diagonal interaction matrix elements. Such strong mixture is essential to explain the observed E2 transition properties of $N=50$ isotones $^{96}$Pd and $^{94}$Ru.