Proton inelastic scattering experiments at energy Ep=200 MeV and a spectrometer scattering angle of 0° were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance (IVGDR). Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour may be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA) calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data.
Donaldson, L. M., Bertulani, C. A., Carter, J., Nesterenko, V. O., von Neumann-Cosel, P., Neveling, R., … Tamii, A. (2018). Deformation dependence of the isovector giant dipole resonance: The neodymium isotopic chain revisited. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 776, 133–138. https://doi.org/10.1016/j.physletb.2017.11.025