Elastic and inelastic proton scattering from 116Cd

Abstract

The differential cross sections for elastically and inelastically scattered 12 MeV protons from 116Cd have been measured for 18 groups to levels below ≈ 2.8 MeV. The elastic scattering was fitted by searching for the best parameters of an optical model. The observed cross sections for excitation of the one-phonon 2 + and 3 − states were compared to the predictions of both the DWBA and coupled-channel theories. Distortion parameters were extracted and compared to those determined from E2 transition probabilities. The coupled-channel theory was used to calculate cross sections for the one-octupole-one-quadrupole and two-quadrupole phonon states. States at 2.041, 2.115 and 2.296 MeV were fitted by means of the 1 −, 3 − or 5 −, and 3 − octupole-quadrupole coupled-channel calculations, respectively. Fits to the two-quadrupole phonon-like states were obtained by assuming an admixture of the one-phonon state in their description. The amplitudes of these admixed wave functions were calculated from both the proton scattering and Coulomb excitation experimental results and it was found that the onephonon amplitudes, especially for the second 2 + states, are large. The results for 116Cd are compared with those obtained from inelastic proton scattering and Coulomb excitation of other nuclei in this mass region to determine systematic trends.