The effect of an octupole component in the intrinsic mean field at high spin is demonstrated by a Woods-Saxon-Bogolyubov cranking calculation. The nature of nuclear rotation becomes nearly collective instead of collective plus single-particle, because octupole couplings with $\Delta l$ up to 3 "dilute" the high-$j$ shells. Theory is consistent with experimental data on ${}_{}{}^{222}{}_{}{}^{}\mathrm{Th}$ and could be tested further by studying the properties of rotating quasiparticles in neighboring odd-mass nuclei.

• Received 18 November 1983

DOI:https://doi.org/10.1103/PhysRevLett.52.1272