Interacting excited rotational bands

The role of the rotating mean field and residual interactions is discussed on the basis of recent experimental interaction matrix elements and distrib ution of level distances. Based on a careful identification of the rotation al bands in four rare-earth nuclei, carried out earlier, most of the intera ctions are found to be generated by a two-body residual interaction. Some h indrance is observed with respect to changes in the K quantum number. Level distance distributions address in a more general way the question of the i ndependence of excitations within rotational states. Both types of experime ntal information, band interactions and level distances, are in general acc ordance with mean field bands interacting with a standard surface-delta int eraction.