In ($\alpha$,${\alpha }^{\prime }$) measurements on spherical ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$ and deformed ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$, the cross sections and energies of the two components of the isoscalar giant resonance are found to be consistent with a splitting of the giant monopole resonance in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ into two components of roughly equal strength. One component remains close to the giant-monopole-resonance energy of ${}_{}{}^{144}{}_{}{}^{}\mathrm{Sm}$ while the second is coincident with the giant quadrupole resonance. This is shown to be consistent with simple schematic-model predictions.

• Received 28 January 1980

DOI:https://doi.org/10.1103/PhysRevLett.45.1670