High-Spin States in Transuranium Nuclei ^242,244Pu

We investigate the structure of yrast bands in the transuranium nuclei ²⁴²Pu and ²⁴⁴Pu in the framework of the projected shell model, which is a fully quantum mechanical and microscopic approach. It is found that an appropriate modification of the standard Nilsson spin−orbital parameters in the N=6 proton shell is necessary to correctly describe the high−spin backbending phenomenon in nucleus ²⁴⁴Pu. In order to test whether this modification is correct, the same modified parameters are used to calculate the yrast band of its neighboring isotope ²⁴²Pu. It is found that without this modification, a backbending will occur at spin I=20, which is not supported by the experimental data.