QUANTAL BIFURCATIONS IN ROTATIONAL SPECTRA OF SOME ODD ATOMIC-NUCLEI

To show the existence of precursor phenomena of the transition order - -> chaos in atomic nuclei a simple analysis has been made, based on a recent criterion proposed by Pavlichenkov. The basic idea is that non- linear effects in rotational bands should lead to bifurcation, which q ualitatively changes the spectrum for one of the nuclear excitation br anches. Experimental data concerning the isotopes of Er, Hf, Yb, Os, D y, W strongly support the above criterion.