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

Abstract

$\alpha$ 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° and 80°. 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.