Non-trivial aspects of the onset of nuclear collectivity: Static moments

Abstract

We consider several topics concerning static magnetic dipole and electric quadrupole moments ($\mu$ and $Q$) as signatures of the onset of nuclear collectivity. Having previously noted that in $^{50}\mbox{Cr}$ there is an abrupt change of sign in $Q$ of yrast states with $J^{\pi}=10^+, 12^+$, and $14^+$ relative to lower $J$ states, we discuss whether these states are oblate or prolate. We next show that configuration mixing leads to much larger changes in $Q$ than in $\mu$. We then look for other bands of interest in $^{50}\mbox{Cr}$. Finally we discuss the Jolos-von Brentano relationship which relates $Q$ of $2^+_1$ states to $B({\rm E2})$'s for transitions from and to the $2^+_1$ states.