Microscopic Description of Quasirotational Bands

A microscopic cranking model is introduced for vibrational nuclei, thus extending the foundation for the phenomenological variable-moment-of-inertia model. The negative value of ${\mathcal{I}}_0$ then emerges naturally. The cranking model approximates energies, static moments, and transition probabilities within the quasirotational subspace. An illustrative application is made to the exactly soluble Moszkowski model.