"Bi-Modal" Isoscalar Giant Dipole Strength In Ni-58

The strength distribution of the isoscalar giant dipole resonance (ISGDR) in Ni-58 has been obtained over the energy range 10.5-49.5 MeV via extreme forward angle scattering (including 0 degrees) of 386 MeV alpha particles. We observe a "bi-modal" El strength distribution for the first time in an A < 90 nucleus. The observed ISGDR strength distribution is in reasonable agreement with the predictions of a recent RPA calculation. (c) 2006 Elsevier B.V. All rights reserved.