High-k Structures under Extreme Conditions

High-K isomer decay rates are compared and interpreted, with an emphasis on the spin degree of freedom. It is argued that high-K values do not in themselves lead to K mixing. Rather, evidence is presented that the most important consideration is the isomer energy relative to a rotor whose moment of inertia is approximately 85% of the rigid-body value. The high-spin limit to the occurrence of high-K isomers is then discussed in connection with predictions of competing oblate rotation-aligned structures. Finally, some observations are made regarding the use of K isomers as a tool to access exotic nuclei, including superheavy elements, and exotic nuclear structures.