An \textit{Ab Initio} Study of $\alpha $ --Pu

Hybrid density functionals, which replace a fraction of density functional theory exchange with exact Hartree-Fock exchange has been used to study the electronic, geometric, and magnetic properties of $\alpha $ -- Pu. Different fractions of Hartree-Fock exchange have been used and the computations have been performed using the all-electron \underline {f}ull-\underline {p}otential \underline {l}inearized \underline {a}ugmented \underline {p}lane \underline {w}ave plus \underline {l}ocal \underline {o}rbitals basis method. Pu has been studied at the non-magnetic, ferromagnetic and anti-ferromagnetic configurations with spin-orbit coupling, orbital polarization, and \textit{full} geometry optimizations. The variations of the optimized lattice constants, magnetic moments, bulk moduli, density of states, and the degree of $5f $electron localization with the amount of Hartree -- Fock exchange will be reported. Results will be compared with those of $\delta $ -- Pu for which the performance of the hybrid functionals did \textit{not} seem superior to that of the pure density functionals.\footnote{R. Atta-Fynn and A. K. Ray, Europhys. Lett. 85, 27008 (2009).}