Anomalous Behavior of High-Spin States inCm248

Abstract

The ground-state band of ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ has been studied up to spin ${28}^{+}$ and tentatively to ${30}^{+}$ by observing $\gamma$ rays following multiple Coulomb excitation with use of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ ions at 5.3 MeV/u. A smooth, gradual increase in the effective moment of inertia is seen at lower spin with an anomalous forward bend above spin ${22}^{+}$. Calculations are presented which indicate that this behavior including the forward bend can be understood in terms of the alignment of single-particle angular momenta along the rotation axis.