First observation of rotational structures in Re 168
We assigned first rotational sequences to the odd-odd nucleus 168 Re. Coincidence relationships of these structures with rhenium x rays confirm the isotopic assignment, while arguments based on the γ-ray multiplicity (K-fold) distributions observed with the new bands lead to the mass assignment. Configurations for the two bands were determined through analysis of the rotational alignments of the structures and a comparison of the experimental B(M1)/B(E2) ratios with theory. Tentative spin assignments are proposed for the πh 11/2 νi 13/2 band, based on energy level systematics for other known sequences in neighboring odd-odd rhenium nuclei, as well as on systematics seen for the signature inversion feature that is well known in this region. Furthermore, the spin assignment for the πh 11/2 ν(h 9/2 /f 7/2 ) structure provides additional validation of the proposed spins and configurations for isomers in the 176 Au → 172 Ir → 168 Re α-decay chain.