Search

Abstract: Using the LCGTO-DFT+U methodology, we analyze the potential effect of self-interaction artifacts in standard Kohn–Sham (KS) density functional calculations on geometries, vibrational frequencies, and bonding for the example of the uranyl (VI) dication, both without and with explicit aqua ligands. We attribute the bent structure of the uranyl moiety in the penta-aqua complex to the limited accuracy of the Coulomb interaction of the U 5f orbitals afforded by common local or gradient-corrected exchange–correlation functionals. In particular, with scalar relativistic, all-electron Douglas–Kroll–Hess calculations we demonstrate that the distorted geometry of the uranyl penta-aqua complex is essentially rectified by the inclusion of a small positive on-site repulsion parameter, U eff, for the 5f shell of the uranium atom. [ABSTRACT FROM AUTHOR]

Abstract: Using the DFT+U methodology with a localized basis set, we studied the role of Lu 4f orbitals in the bonding of LuF3. We carried out scalar relativistic all-electron Douglas–Kroll–Hess DFT calculations of geometry, atomization energy, and vertical ionization potentials without and with the Hubbard term. The on-site repulsion parameter U eff for Lu 4f orbitals was estimated from reference atomic data. With U eff >0, atomic localization of the valence 4f-like molecular orbitals is recovered, thus removing the spurious mixing of Lu 4f and F 2p orbitals present in standard Kohn–Sham calculations, while the molecular properties of LuF3 remained unchanged. [Copyright &y& Elsevier]

Copyright of International Journal of Quantum Chemistry is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)