Toward complete spectroscopy of ¹²⁸Pr and rotational structures in ¹²⁶Pr

Over 240 transitions and three new rotational bands have been observed in the well-deformed, odd-odd ₅₉¹²⁸Pr₆₉ nucleus. The high-spin states were populated in two experiments using the ⁹²Mo(⁴⁰Ca,3pn) reaction at beam energies of 170 and 184 MeV. Several structures were confirmed in the former experiment using the Clarion and HyBall arrays with the recoil mass spectrometer at Oak Ridge National Laboratory. Gammasphere, in conjunction with the Microball, were employed in the latter experiment at Argonne National Laboratory to extend the sequences to very high spins. Rotational structures in ¹²⁶Pr were also identified in the α p n channel of the same reaction. The recent discrepancies of spin assignments for the yrast bands in ^126,128Pr and the interpretation of the lowest crossing in the πh_11/2 band in ¹²⁷Pr are discussed. An adiabatic crossing of the intruder i_13/2 neutron with one of the normal-deformed bands in ¹²⁸Pr is observed at high rotational frequency. Experimental trends in the signature inversion phenomenon of the πh_11/2νh_11/2 bands in the A 130 region are defined and prove to be surprisingly irregular with respect to those found in the πh_11/2νi_13/2 bands of the A 160 region.