Compressional-Mode Giant Resonances in Deformed Nuclei

Background-free inelastic scattering spectra have been obtained for the Sm isotopes with 386 MeV α particles at forward angles (including 0°) to investigate the effect of deformation on the compressional-mode giant resonances. The strength distributions for the isoscalar giant resonances (L ≤ 3) have been extracted for ¹⁴⁴Sm, ¹⁴⁸Sm, ¹⁵⁰Sm, ¹⁵²Sm, ¹⁵⁴Sm. We have observed that the effects of deformation are different for the low- and high-excitation-energy components of the isoscalar giant dipole resonance in ¹⁵⁴Sm. Evidence for the theoretically predicted coupling between the isoscalar dipole resonance and the high-energy octupole resonance is reported.