Toward Complete Spectroscopy Of Pr-128 And Rotational Structures In Pr-126

Over 240 transitions and three new rotational bands have been observed in the well-deformed, odd-odd Pr-128(59)69 nucleus. The high-spin states were populated in two experiments using the Mo-92(Ca-40,3pn) 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 Pr-126 were also identified in the alphapn channel of the same reaction. The recent discrepancies of spin assignments for the yrast bands in Pr-126,Pr-128 and the interpretation of the lowest crossing in the pih(11/2) band in Pr-127 are discussed. An adiabatic crossing of the intruder i(13/2) neutron with one of the normal-deformed bands in Pr-128 is observed at high rotational frequency. Experimental trends in the signature inversion phenomenon of the pih(11/2)nuh(11/2) bands in the Aapproximate to130 region are defined and prove to be surprisingly irregular with respect to those found in the pih(11/2)nui(13/2) bands of the Aapproximate to160 region.