NONADIABATIC BEHAVIOR OF E2 TRANSITIONS IN ER-166

The non-adiabatic behavior of the gamma-to-ground E2 transitions in Er -166 is discussed and the influence on this behaviour of the Coriolis mixing between the ground and gamma bands through the 1+ states, inclu ding the low-energy 'scissors' mode, is analysed. It is demonstrated t hat in the RPA consideration with exact extraction of spurious admixtu res connected with the violation of rotational invariance the Coriolis coupling between the ground and 1+ bands is exactly zero. The Corioli s interaction between the gamma and 1+ bands cannot alone account for the non-adiabatic effects in Er-166, in spite of the coherent characte r of influence of different 1+ states on the E2 transitions. An apprec iable gamma deformation, which is known to result in an additional mix ing of the bands, should be also taken into account.