The competition between collective and single particle behaviour in the odd-odd isotopes 128,130La

TLDR: In this article, excited states in the odd-odd nuclei 128,130La have been investigated to high spin using gamma-ray spectroscopy, and two distinct bands are seen, one based on a pi h11/2(X) nu h 11/2/2 structure and the other based on pi h 11 /2/X/nu g7/2 configuration.

Abstract: Excited states in the odd-odd nuclei 128,130La have been investigated to high spin using gamma -ray spectroscopy. Two distinct bands are seen, one based on a pi h11/2(X) nu h11/2 structure and the other on a pi h11/2(X) nu g7/2 configuration. Backbends are observed in both configurations for both nuclei and the nature of the particles responsible can be conclusively proved. Experimental variation in the energy-level signature splitting and B(M1)/B(E2) ratios are discussed in terms of the polarising effects of the odd proton and odd neutron on the soft collective core. The results are discussed in terms of the cranked shell model, odd-odd particle-rotor calculations and total Routhian surface calculations. They are also compared to neighbouring odd and odd-odd systems.