Excited states in Ce-138 have been studied via the C-12(Ce-138,Ce-138(*)) Coulomb excitation reaction at 480 MeV. Relative cross sections have been determined from the gamma-ray yields observed with Gammasphere. The E2 and M1 strength distributions between the lowest six 2(+) states up to 2.7 MeV enables us to identify the 2(4)(+) state in Ce-138 as the dominant fragment of the one-phonon 2(1,ms)(+) mixed-symmetry state. Mixing between this level and a nearby isoscalar state is observed and is more than 4 times larger than in the neighboring isotone Ba-136. This is direct evidence that the stability of mixed-symmetry states strongly depends on the underlying subshell structure.
|Number of pages||4|
|Journal||Physical Review Letters|
|Publication status||Published - 31 Mar 2006|
- MIXED-SYMMETRY STATES