Alignments, additivity, and signature inversion in odd-odd {sup 170}Ta : a comprehensive high-spin study.

High-spin states (I < or approx. 50(Planck constant/2pi)) of the odd-odd nucleus {sup 170}Ta have been investigated with the {sup 124}Sn({sup 51}V,5n) reaction. The resolving power of Gammasphere has allowed for the observation of eleven rotational bands (eight of which are new) and over 430 transitions (approx350 of which are new) in this nucleus. Many interband transitions have been observed such that the relative spins and excitation energies of the 11 bands have been established. This is an unusual circumstance in an odd-odd study. Configurations have been assigned to most of these bands based upon features such as alignment properties, band crossings, B(M1)/B(E2) ratios, and the additivity of Routhians. A systematic study of the frequency at which normal signature ordering occurs in the pih{sub 9/2}nui{sub 13/2} band has been performed and it is found that its trend is opposite to that observed in the pih{sub 11/2}nui{sub 13/2} bands. A possible interpretation of these trends is discussed based on a proton-neutron interaction.