Elastic and Inelastic Proton Scattering fromPd106andPd108

Abstract

Angular distributions of elastically and inelastically scattered 12- and 13-MeV protons from ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$ and ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$ have been measured for angles between 24° and 165°. Quadrupole and octupole deformation parameters, ${\beta }_2$ and ${\beta }_3$, were extracted from the experimental cross sections by means of the distorted-wave direct-interaction theory. They are: ${\beta }_2=0.25\mathrm{}$ and ${\beta }_3=0.15\mathrm{}$ for ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$, and ${\beta }_2=0.23\mathrm{}$ and ${\beta }_3=0.14\mathrm{}$ for ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$. These are consistent with values obtained through Coulomb-excitation studies. The octupole states were observed at 2.07 MeV in ${}_{}{}^{106}{}_{}{}^{}\mathrm{Pd}$ and 2.03 MeV in ${}_{}{}^{108}{}_{}{}^{}\mathrm{Pd}$. Differential cross sections of the two-quadrupole phonon states have been compared with the predictions of the coupled-channels theory as extended by Tamura. To achieve reasonable agreement between experiment and theory for excitation of the second $2^{+}$ level, it was necessary to admix the one- and two-quadrupole phonon states. Energies and cross sections at one angle for a number of other levels below 3.2 MeV are also reported.