Complex band interactions in 170

Inelastic excitation of Er by a U beam, studied at near-barrier energies, has led to the observation of unusual features in rotational bands built on low-lying vibrations. The population of the high-spin members of the K50, b-vibrational band is enhanced due to mixing with the K52, g-vibrational band at spin 4. Strong mixing of the K50 band with a rotationally aligned 2 qp band results in this band losing its b-vibrational character and in a rapid gain in spin alignment leading to a crossing with the ground-state band between spins 20 and 22. The low-lying K53 band also is populated. It subsequently decays to both the g-vibrational and the ground-state bands. The occurrence of appreciable K-forbidden E2 transitions from the K53 to the ground-state band is attributed to mixing with the K52 band, caused by the interaction between the quadrupole g-vibrational and the hexadecapole vibrational motions.