A non-empirical calculation of 2p core-electron excitation in compounds with 3d transition metal ions using ligand-field and density functional theory (LFDFT)

Abstract

and interpretation of the transition metal L 2,3 -edge X-ray absorption spectra.

Theoretical insight into the magnetic circular dichroism of uranium N6,7‐edge X‐ray absorption

“…We use the LFDFT method, [21][22][23] at the extended level with a three-open-shell electron configuration, [15,26] to calculate the multiplet energies E and multielectronic eigenfunctions ψ. The LFDFT treats near-degeneracy correlation using an ad hoc configuration interaction algorithm within active Kohn-Sham molecular orbitals that are formally identified as having predominant uranium 4f, 5f, and 6d parentage.…”

“…[19,20] In this work, we report a fully theoretical study of the uranium N 6,7 -edge XAS and XMCD of uranocene, whereby core 4f electrons are coupled with valence 5f and 6d. [14,15] We use the ligand-field density functional theory (LFDFT) method, [21][22][23] a nonempirical computational chemistry tool that allows calculation of multiplet energies of multiple open-shell electron configurations at the density functional theory (DFT) level of theory.…”

“…4f 13 5f 2 6d 1 electron transition. This work also has a methodical perspective by extending the scope of LFDFT [21][22][23] to take into consideration the presence of external magnetic field, incorporating into the model Hamiltonian for three-open-shell electron configuration a term for Zeeman interaction. [24] This allows us to model XAS spectra with the left-circularly and right-circularly polarized X-ray, demonstrating evidence of XMCD for tetravalent U 4+ ions in coordination compounds.…”

A DFT-based theoretical model for the calculation of spectral profiles of lanthanide M4,5-edge x-ray absorption

“…Equation 12complies with the fundamental concept of ligand-field theory, 34,35 where electrons are moving in a central-field independent of the atomic ml basis functions. 34,35 Although the spin-orbit coupling constants ζ 3d and ζ 4f can also be obtained using the radial functionsR 3d andR 4f , [36][37][38][39] it is more convenient to take advantage of the spin-orbit ZORA method 26,27 in ADF. [11][12][13] The primary advantage of using the ZORA method is that the spin-orbit coupling interaction is self-consistently treated.…”

Non-empirical calculation of X-ray magnetic circular dichroism in lanthanide compounds

“…9 Hybrid approaches, in which ligand-field parameters of LFMT are obtained by electronic structure calculations, have been demonstrated for 3d transition metals XAS. 7,10,11 The feasibility in the case of 4f lanthanides and 5f actinides application is possible but much effort is needed to establish a fully nonempirical model. 12,13 Here, we demonstrate that ligand-field density-functional theory (LFDFT) [14][15][16][17] is able to reproduce in very detail the XMCD spectra as well as the corresponding XLD.…”