In the late 1980s, high-spin superdeformed rotational bands were observed in other regions of the periodic table.
Specific elements include ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold, and mercury.
The existence of superdeformed states occurs because of a combination of macroscopic and microscopic factors, which together lower their energies, and make them stable minima of energy as a function of deformation.
However, the curve may become soft with respect to high deformations because of the Coulomb repulsion (especially for the fission isomers, which have high Z) and also, in the case of high-spin states, because of the increased moment of inertia.
For nuclei near these magic numbers, the shell correction creates a second minimum in the energy as a function of deformation.