Level structures in the odd-odd heavy actinide ²⁵⁴₁₀₃Lr₁₅₁

Occurrence of Long-lived Isomers (LLI) in deformed nuclei has been the subject of study for more than four decades. An early survey of this phenomenon had concluded that such occurrences are much more likely in the odd-odd deformed nuclei. In particular, N=151 isotones in the actinide region presents a promising domain for such investigation due to the following reasoning. The N=151^st neutron orbital 9/2^-(734) has large energy gaps above and below it. On the other side high (>5/2) spin p-orbitals are observed in the deformed actinides. Coupling of these (n,p) orbitals results in several 2qp GM doublets with large spin difference (ΔK≥5). With no significant γ-transition connecting the respective members of each doublets, their relative ordering/energy placement remains undetermined. As a part of our ongoing investigations on the level structures of odd-odd actinides, we present here the results of our analysis of the low-lying level structure of the heaviest N=151 odd-odd actinide, namely ₁₀₃²⁵⁴Lr₁₅₁