Octupole Strength Research Articles

Core Excitations inAg107,Ag109,In113,In115,Sb121, andSb123Resulting from Inelastic Scattering of 42-MeV Alpha Particles

$\ensuremath{\alpha}$ particles of 42-MeV energy were elastically and inelastically scattered from isotopically enriched targets of $^{113}\mathrm{In}$, $^{115}\mathrm{In}$, $^{107}\mathrm{Ag}$, $^{109}\mathrm{Ag}$, $^{121}\mathrm{Sb}$, and $^{123}\mathrm{Sb}$. Angular distributions were measured for a number of states in each isotope for angles between 30\ifmmode^\circ\else\textdegree\fi{} and 80\ifmmode^\circ\else\textdegree\fi{}. The results are compared with the predictions of the simple excited-core model with respect to the strengths and energies of the excitations. In all six isotopes, states were found which accounted for all of the one-quadrupole-phonon vibrational strength observed in the neighboring even-even nuclei. In $^{113}\mathrm{In}$, $^{115}\mathrm{In}$, and $^{121}\mathrm{Sb}$, multiplets of states were seen which contained all of the strength of the octupole vibrational states of the even neighbors. In $^{107}\mathrm{Ag}$ and $^{109}\mathrm{Ag}$, only half of the expected octupole strength was observed. In both silver isotopes, a number of states were seen which have approximately the proper strengths and excitation energies to arise from the coupling of the odd proton to a two-phonon vibrational state of the core.

Fractionization of the octupole strength in 90Zr

The 90Zr ( α, α′) reaction has been studied at 31 MeV with 80 keV resolution. Three octupole states have been found between 5 and 6 MeV with a total strength of 31% of the lowest 3 − state. This extends the study of the fractionization of the octupole state previously found in the f 7 2 shell.