Dipole excitations in the vibrational nucleus112Cd

Abstract

The strength distribution of low-lying dipole excitations in the medium-weight vibrational nucleus ${}^{112}\mathrm{Cd}$ was investigated by means of nuclear resonance fluorescence experiments (NRF) performed at the bremsstrahlung beam of the Stuttgart Dynamitron accelerator (end-point energy 4.1 MeV). Detailed information on excitation energies, spins, decay widths, and transition probabilities of about 20 new spin-1 states in ${}^{112}\mathrm{Cd}$ has been obtained. In comparison with comprehensive spectroscopic information available for ${}^{112}\mathrm{Cd}$ conclusions on the parities of the lowest states can be made. A strongly excited ${J}^{\ensuremath{\pi}}{=1}^{\ensuremath{-}}$ state is interpreted as the ${1}^{\ensuremath{-}}$ member of the quadrupole-octupole coupled quintuplet. The observed transition intensities are described in the framework of the interacting boson model and compared with those obtained from recent nuclear resonance fluorescence experiments on the neighboring Cd isotopes ${}^{113,114}\mathrm{Cd}.$