A Hybrid Density Functional Study on PuN

Abstract

The structural, magnetic, electronic, dynamical and thermodynamic properties of PuN have been studied within the frameworks of the density-functional theory, DFT+U and hybrid DFT. The calculations have been performed using the full-potential-linearized augmented plane-wave method. The ferromagnetic and antiferromagnetic configurations are considered in this work. The lattice constants, bulk moduli, densities of states, and thermodynamic data have been computed and compared to available experimental data and other theoretical calculations published in the literature. Total energy results obtained with DFT+U and hybrid DFT indicate that the ground state of PuN is antiferromagnetic, in agreement with experiment. The chemical bonds between Pu and N have a mixture of covalent and ionic components, but the ionic character is stronger than covalent character. The phonon dispersion curves and the optical-mode frequencies are also reported. At last, the effect of spin-orbit coupling on the structural, magnetic, and electronic properties of PuN has been discussed.

Exploring the sub-stoichiometric behavior of plutonium mononitride

“…11 In Fig. 1, the lime triangle, green hexagon, and fuchsia square represent the theoretical data from Atta-Fynn et al, 8 Murugan et al, 21 Rong Yang et al 24 They are 4.953 Å, 4.782 Å, 4.944 Å, respectively, and our calculation is 4.922 Å. Our calculation is a comparative approximation in comparison with the experimental data.…”

“…23 The structural, magnetic, electronic, dynamical and thermodynamic properties of PuN have been examined by Rong Yang et al within the frameworks of density functional theory, DFT+U and hybrid DFT. 24 Actually, there was still a lack of clarity about the substoichiometric behavior of PuN, which is important for understanding its physical and chemical properties. Previous experimental work about the sub-stoichiometric behavior of PuN was mainly contributed by Ogawa et al In 1993, Ogawa et al calculated N/Pu by the vapor pressure data: N/Pu ¼ 0.978 at 2000 K, 25 and calculated N/Pu from other data: N/Pu ¼ 0.98 at 1600-2000 K by Kent and Leary 25,26 and N/Pu ¼ 0.97 at 2000-2400 K by Alexander.…”