ISOSCALAR MONOPOLE STRENGTH IN FE-56 AND NI-58

The giant resonance region up to E(x)=30 MeV was studied in Ni-58 with inelastic scattering of 240 MeV alpha particles at small angles inclu ding 0 degrees. It is shown that the total isoscalar monopole strength in the region E(x)=12 to 25 MeV in Ni-58 is < 50% of the EO energy-we ighted sum rule, and that the centroid of the EO strength E(GMR) > 24. 8 MeV in contrast to the E(GMR)approximate to 17 MeV expected from sys tematics of other nuclei. For Fe-56, the angular distribution for a pe ak at E(x) = 16.15 MeV having a width Gamma = 5.52 MeV is fit well by an L=2 DWBA calculation exhausting 56% of the E2 energy- weighted sum rule. The angular distribution for a peak at E(x) = 19.2 MeV having a width Gamma = 7.45 MeV is fit well by a combination of 100% of the E1 sum rule and 12% of the EO sum rule for tile breathing mode.