Motional narrowing and ergodic bands in excited superdeformed states of 194Hg

Phys Rev Lett. 2008 Mar 14;100(10):102501. doi: 10.1103/PhysRevLett.100.102501. Epub 2008 Mar 14.

Abstract

The E(gamma) - E(gamma) coincidence spectra from the electromagnetic decay of excited superdeformed states in (194)Hg reveal surprisingly narrow ridges, parallel to the diagonal. A total of 100-150 excited bands are found to contribute to these ridges, which account for nearly all the unresolved E2 decay strength. Comparison with theory suggests that these excited bands have many components in their wave functions, yet they display remarkable rotational coherence. This phenomenon can be explained in terms of the combination of shell effects and motional narrowing.