Study of band mixing in the rotational quasi-continuum

The rotational continuum for normally deformed nuclei of the rare earth region is investigated making use of statistical analysis methods, With these techniques it is possible to extract information on the rotational motion from the region of high level density, in this connection, two points will be discussed: i) the important role of the residual interaction in the description of the experimental data and ii) the dependence of the mixing among rotational bands on the symmetry quantum numbers of the nuclear states, This last point was investigated for the nucleus Er-163 for which it has been found that the gamma-cascades feeding into low-K bands are different from those feeding high-K bands, This result indicates that the K-selection rules are effective for excited rotational bands within the angular momentum 30h less than or equal to I less than or equal to 40h.