Nuclear shape dynamics at different energy scales

We present a model scheme for description of odd-mass nuclei based on the consideration of quadrupole-octupole vibration-rotation motion in the even-even core and reflection-asymmetric axially-deformed potential for the odd-nucleon motion. Having incorporated fully microscopically determined K-mixing and decoupling effects due to the Coriolis interaction between the nucleon and the core, the model allows otherwise forbidden electromagnetic transitions between states built on different intrinsic configurations. We demonstrate the application of the model to the nucleus ²²⁹Th showing that together with the overall quadrupole-octupole structure of the spectrum the theory is capable to explain the presence of the extremely low-energy isomer at 7.8 eV as well as to predict its γ-decay. This result suggests that the fine interplay between the collective and single-nucleon motions may govern dynamical effects in a wide range of excitations between the nuclear and atomic energy scales.