Asok K. Ray

Density functional study of the actinide nitrides

The full potential all electron linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method, as implemented in the suite of software WIEN2K, has been used to systematically investigate the structural, electronic, and magnetic properties of the actinide compounds AnN (An = Ac, Th, Pa, U, Np, Pu, Am). The theoretical formalism used is the generalized gradient approximation to density functional theory (GGA-DFT) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. Each compound has been studied at six levels of theory: non-magnetic (NM), non-magnetic with spin-orbit coupling (NM+SOC), ferromagnetic (FM), ferromagnetic with spin-orbit coupling (FM+SOC), anti-ferromagnetic (AFM), and anti-ferromagnetic with spin-orbit coupling (AFM+SOC). The structural parameters, bulk moduli, densities of states, and charge distributions have been computed and compared to available experimental data and other theoretical calculations published in the literature. The total energy calculations indicate that the lowest energy structures of AcN, ThN, and PaN are degenerate at the NM+SOC, FM+SOC, and AFM+SOC levels of theory with vanishing total magnetic moments in the FM+SOC and AFM+SOC cases, making the ground states essentially non-magnetic with spin-orbit interaction. The ground states of UN, NpN, PuN, and AmN are found to be FM+SOC at the level of theory used in the present computations. The nature of the interactions between the actinide metals and nitrogen atom, and the implications on 5f electron delocalization and localization are discussed in detail.

Ab initio full-potential fully relativistic study of atomic carbon, nitrogen, and oxygen chemisorption on the (111) surface of δ-Pu

First-principles total-energy calculations within the framework of generalized gradient approximation to density-functional theory have been performed for atomic carbon, nitrogen, and oxygen chemisorption on the (111) surface of

All-electron LCGTO calculations for uranium dioxide

\ensuremath{\delta}\text{\ensuremath{-}}\mathrm{Pu}

First-principles electronic structure study of the quantum size effects in (111) films of δ -plutonium

. The full-potential all-electron linearized augmented plane wave plus local orbitals method with the Perdew-Burke-Ernzerhof exchange-correlation functional has been employed. Chemisorption energies have been optimized with respect to the distance of the adatom from the Pu surface for four adsorption sites, namely, the top, bridge, hollow fcc, and hollow hcp sites, with the adlayer structure corresponding to a coverage of 0.50 of a monolayer in all cases. Computations were carried out at two theoretical levels, one without spin-orbit coupling (NSOC) and one with spin-orbit coupling (SOC). For NSOC calculations, the hollow fcc adsorption site was found to be the most stable site for C and N with chemisorption energies of 6.272 and

Full-potential LAPW electronic structure study of δ - plutonium and the (001) surface

6.504\phantom{\rule{0.3em}{0ex}}\mathrm{eV}

On the electronic structures of GaAs clusters

, respectively, while the hollow hcp adsorption site was found to be the most stable site for O with chemisorption energy of

Does hybrid density functional theory predict a non-magnetic ground state for δ-Pu?

8.025\phantom{\rule{0.3em}{0ex}}\mathrm{eV}

Many-body perturbation theory applied to small germanium clusters

. For SOC calculations, the hollow fcc adsorption site was found to be the most stable site in all cases with chemisorption energies for C, N, and O being 6.539, 6.714, and

Electronic structures and bonding of oxygen on plutonium layers

8.2\phantom{\rule{0.3em}{0ex}}\mathrm{eV}

Anomalous spectroscopy of Li4- clusters.

, respectively. The respective distances of the C, N, and O adatoms from the surface were found to be 1.16, 1.08, and