A study of positive parity yrast bands of 230–240U and 236–242Pu nuclei

The projected shell model is used to study the yrast positive parity bands in 230–240U and 236–242Pu nuclei. The energy levels, deformation systematics, E2 transition probabilities and g-factors are calculated. The calculation reproduces the observed positive parity yrast bands and B(E2) transition probabilities. The observed deformation trend of low-lying states in Uranium and Plutonium nuclei depends on the occupation of down-sloping components of high j orbits in the valence space. The low-lying states of yrast spectra are found to arise from 0-quasiparticle (qp) intrinsic states, whereas the high spin states possess multi-qp structure. The theoretical results of g-factors of Pu isotopes predict an increase in g-factors at higher spins arising from the alignment of protons in 1i13/2 orbit. The predicted values of B(E2)s and g-factors for higher spin states in Pu isotopes have to be verified experimentally.