Nontrivial aspects of the onset of nuclear collectivity: Static moments

We consider several topics concerning static magnetic dipole and electric quadrupole moments (μ and Q) as signatures of the onset of nuclear collectivity. Having previously noted that in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$ there is an abrupt change of sign in Q of yrast states with ${\mathit{J}}^{\mathrm{\pi }}$=${10}^{+}$,${12}^{+}$, 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 μ. We then look for other bands of interest in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$. Finally we discuss the Jolos–von Brentano relationship which relates Q of $2_1^{+}$ states to B(E2)’s for transitions from and to the $2_1^{+}$ states. © 1996 The American Physical Society.