Excited states in 58,60,62 Ni were populated via inelastic proton scattering at the Australian National University as well as via inelastic neutron scattering at the University of Kentucky Accelerator Laboratory. The Super-e electron spectrometer and the CAESAR Compton-suppressed HPGe array were used in complementary experiments to measure conversion coefficients and δ(E2/M 1) mixing ratios, respectively, for a number of 2 + → 2 + transitions. The data obtained were combined with lifetimes and branching ratios to determine E0, M 1, and E2 transition strengths between 2 + states. The E0 transition strengths between 0 + states were measured using internal conversion electron spectroscopy and compare well to previous results from internal pair formation spectroscopy. The E0 transition strengths between the lowest-lying 2 + states were found to be consistently large for the isotopes studied.

The time differential perturbed angular distribution technique with LaBr 3 detectors has been applied to the I π = 11 2 − isomeric state (E x = 846 keV, τ = 107 ns) in 107 Cd, which was populated and recoil-implanted into a gadolinium host following the 98 Mo(12 C, 3n) 107 Cd reaction. The static hyperfine field strength of Cd recoil implanted into gadolinium was thus measured, together with the fraction of nuclei implanted into field-free sites, under similar conditions as pertained for a previous implantation perturbed angular distribution g-factor measurement on the I π = 10 + state in 110 Cd. The 110 Cd g(10 +) value was thereby reevaluated, bringing it into agreement with the value expected for a seniority-two νh11 /2 configuration.

Background: The even cadmium isotopes near the neutron midshell have long been considered among the best examples of vibrational nuclei. However, the vibrational nature of these nuclei has been questioned based on E2 transition rates that are not consistent with vibrational excitations. In the neighbouring odd-mass nuclei, the g factors of the low-excitation collective states have been shown to be more consistent with a deformed rotational core than a vibrational core. Moving beyond the comparison of vibrational versus rotational models, recent advances in computational power have made shell-model calculations feasible for Cd isotopes. These calculations may give insights into the emergence and nature of collectivity in the Cd isotopes.Purpose: To investigate the nature of collective excitations in the A ∼ 100 region through experimental and theoretical studies of magnetic moments and electromagnetic transitions in 111 Cd. Method:The spectroscopy of 111 Cd has been studied following Coulomb excitation. Angular correlation measurements, transient-field g-factor measurements and lifetime measurements by the Doppler-broadened line shape method were performed. The structure of the nucleus was explored in relation to particle-vibration versus particlerotor interpretations. Large-scale shell-model calculations were performed with the SR88MHJM Hamiltonian.Results: Excited-state g factors have been measured, spin assignments examined and lifetimes determined. Attention was given to the reported 5/2 + 753-keV and 3/2 + 755-keV states. The 3/2 + 755-keV level was not observed; evidence is presented that the reported 3/2 + state was a misidentification of the 5/2 + 753-keV state.Conclusions: It is shown that the g factors and level structure of 111 Cd are not readily explained by the particlevibration model. A particle-rotor approach has both successes and limitations. The shell-model approach successfully reproduces much of the known low-excitation structure in 111 Cd.

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The E0 transition strength in the 2 + 2 → 2 + 1 transitions of 58,60,62 Ni have been determined for the first time following a series of measurements at the Australian National University (ANU) and the University of Kentucky (UK). The CAESAR Compton-suppressed HPGe array and the Super-e solenoid at ANU were used to measure the δ(E2/M 1) mixing ratio and internal conversion coefficient of each transition following inelastic proton scattering. Level half-lives, δ(E2/M 1) mixing ratios and γ-ray branching ratios were measured at UK following inelastic neutron scattering. The new spectroscopic information was used to determine the E0 strengths. These are the first 2 + → 2 + E0 transition strengths measured in nuclei with spherical ground states and the E0 component is found to be unexpectedly large; in fact, these are amongst the largest E0 transition strengths in medium and heavy nuclei reported to date.