Bifurcations in the rotational spectra off odd atomic nuclei

A critical phenomenon, the classical analogue of which is bifurcation, is discovered in the rotational bands of strongly deformed odd nuclei. An analysis of the classical and quantum pattern of the phenomenon shows that it involves a change in the correlation between the vectors of the total and nucleon angular momenta. Qualitative changes in the energy spectrum and probabilities for electromagnetic M1 transitions are found which permit one to observe a quantum bifurcation in the high-spin states of odd nuclei. Experimental data are presented which indicate the existence of a bifurcation in the bands of the odd-neutron Yb isotopes