Coulomb and nuclear excitations of ⁷⁰N and ⁶⁸Ni at intermediate energy

The reduced transition probabilities in and the full strength up to in have been determined at the LISE/GANIL facility using the Coulomb-excitation technique at intermediate beam energy on a target. The rays emitted in-flight were detected with an array of crystals. The angles of the deflected nuclei were determined in order to disentangle and extract the Coulomb and nuclear contributions to the excitation of the states. The measured of 1432(124) for falls in the lower part of the published values which clustered either around 1600 or above , while the of 53(7) agrees very well with the two published values. The relatively low of 301(38) for agrees with previous studies and confirms a local magicity at , . Combining the results of the low-energy spectra of and and their shell-model interpretations, it is interesting to notice that four different shapes (spherical, oblate, prolate, and triaxial) are present. Finally, a summed strength of only about has been found experimentally at high excitation energy, likely due to proton excitations across the gap. The experimental distribution of this high-energy excitation agrees with shell-model calculations, but its strength is about two times weaker.