The deformation systematics of the light even-even neodymium isotopes

Abstract

The gamma ray decays of excited states in the nuclei 128,130,132Nd have been identified as the result of measurements of multiple particle-gamma coincidences. The reactions 40Ca + 92Mo and 40Ca + 96Ru were studied at bombarding energies ranging from 147 to 200 MeV. Gamma-ray excitation functions were measured over this energy range. In the case of the 92Mo( 40Ca, 2p) 130Nd reaction, the angular distributions of the emitted gamma rays were also measured at 180 MeV bombarding energy. The lifetimes of the lowest states in the ground-state bands of these nuclei were measured using the recoil distance method. The results are consistent with these nuclei possessing large, permanent, ground state deformations with typical values of ε 2 ≈ 0.3. The ground state rotational bands of all the nuclei studied exhibit band crossings at h ̵ ω c ≈0.32 MeV . This appears to be due to the alignment of h 11 2 protons. The results are discussed in the light of recent potential energy surface and cranked-shell-model calculations.