The available data on some actinide nuclei point to certain significant features of the rotational yrast band and other excited bands. The rotational properties of plutonium isotopes (${}^{236–346}\mathrm{Pu}$) were studied via projected shell model (PSM). Calculations are based on the Hamiltonian of the PSM which includes the formed part of a single particle, the $Q-Q$ force, and the residual interaction of monopole and quadrupole pairings. The results of the calculated energy levels of the yrast band are then compared with available experimental data and a good agreement has been found. The crossing between two-quasiparticle (2qp) excited bands and the ground state band (g band) in the high-spin regions has been analyzed in terms of band diagrams. The upbendings observed in the kinematic moments of inertia ($j^{\left(1\right)}$ MOI) curves for ${}^{236–346}\mathrm{Pu}$ isotopes are due to the effect of two aligning nucleons that occupy excited bands and the $\nu (j_{15/2}$), $\pi (i_{13/2}$) high-$j$ intruder orbits. The PSM successfully reproduces the observed upbending in $j^{\left(1\right)}$ as well as the upturning and downturning in $j^{\left(2\right)}$. For the ${}^{240}\mathrm{Pu}$ isotope, the PSM predicts a simultaneous alignment of neutrons ${\nu }^2 [1/2,-7/2] K^{\pi }$ = $4^{+}$ and protons ${\pi }^2 [-3/2,5/2] K^{\pi }$ = $1^{+}$ bands cross the g band at spin $I=22$. We expect it to be mainly responsible for the disagreement at $I=22$. Furthermore, electric quadrupole transition probabilities $B\left(E2\right)$ and the gyromagnetic factor ($g$ factor) for the yrast band energy levels are also studied.

• Received 10 June 2022
• Accepted 10 November 2022

DOI:https://doi.org/10.1103/PhysRevC.106.064309