Abstract
Deformation of nuclei is present across the nuclear landscape. With the use of experimental techniques, such as Coulomb excitation, this property of nuclei can be probed further and thus can provide a more complete picture of their structure. Lying between two magic number shell closures of 28 and 50, the N ≈ Z ≈ 40 region of the nuclear chart has long been associated with strongly deformed nuclear shapes. The strong deformation present in this area has been confirmed through studies of the lifetimes of N ≈ Z Sr and Zr nuclei. Recent theoretical calculations predict near prolate axial deformation for N = Z and N = Z+2 nuclei between N = Z = 36 and N = Z = 40 (76,78Sr and 80Zr). 80Sr is on the edge of this predicted axially prolate region. In this work, Coulomb excitation of 80Sr was carried out. The first experimental measurement of the spectroscopic quadrupole moment for 80Sr is shown in this work to be Qs(2+1) = 0.45±0.83 0.88 eb. This measurement of Qs is inconsistent with theoretical predictions. As such, this points to the expected region of axially prolate nuclei having somewhat sharply defined edges around the quartet of nuclei: 76,78Sr and 78,80Zr. Further along the nuclear chart, neutron-rich Sr, Zr, and Mo nuclei have been observed to undergo a dramatic evolution, becoming strongly deformed around N = 60. This is sometimes interpreted as a quantum phase transition between “normal” and intruder configurations. A key to understanding this evolution is to observe the configurations in isolation, in regions where this interference can be neglected. A deformed coexisting configuration is inferred from the presence of a 0+2state which decreases in excitation energy with increasing neutron number, which becomes the first-excited state of 98Mo. Another part of this work covers the results of the Coulomb excitation of 96Mo. The values extracted are for B(E2) and spectroscopic quadrupole moments. While in agreement with the literature values of B(E2), there is a significant disagreement with the literature spectroscopic quadrupole moments. The presented results are compared with shell-model calculations using an 88Sr core with a good agreement found, likely indicating that intruder structures do not significantly impact the ground-state structure, in contrast with
the heavier Mo isotopes.