Search for intrinsic collective excitations inSm152

Abstract

The 685 keV excitation energy of the first excited ${0}^{+}$ state in $^{152}\mathrm{Sm}$ makes it an attractive candidate to explore expected two-phonon excitations at low energy. Multiple-step Coulomb excitation and inelastic neutron scattering studies of $^{152}\mathrm{Sm}$ are used to probe the $E2$ collectivity of excited ${0}^{+}$ states in this ``soft'' nucleus and the results are compared with model predictions. No candidates for two-phonon ${K}^{\ensuremath{\pi}}={0}^{+}$quadrupole vibrational states are found. A ${2}^{+},K=2$ state with strong $E2$ decay to the first excited ${K}^{\ensuremath{\pi}}={0}^{+}$ band and a probable ${3}^{+}$ band member are established.