Nonadiabatic behaviour of E2 transitions in<sup>166</sup>Er
Abstract
The nonadiabatic behaviour of the gamma-to-ground E2 transitions in 166Er is discussed and the influence on this behaviour of the Coriolis mixing between the ground and gamma bands through the 1+ states, including the low-energy 'scissors' mode, is analysed. It is demonstrated that in the RPA consideration with exact extraction of spurious admixtures connected with the violation of rotational invariance the Coriolis coupling between the ground and 1+ bands is exactly zero. The Coriolis interaction between the gamma and 1+ bands cannot alone account for the nonadiabatic effects in 166Er, in spite of the coherent character of influence of different 1+ states on the E2 transitions. An appreciable gamma deformation, which is known to result in an additional mixing of the bands should be also taken into account.