In: The Journal of Physical Chemistry A, 2020, vol. 124, no. 1, p. 152–164
The electronic structure of Eu2+ compounds results from a complex combination of strongly correlated electrons and relativistic effects as well as weak ligand–field interaction. There is tremendous interest in calculating the electronic structure as nowadays the Eu2+ ion is becoming more and more crucial, for instance, in lighting technologies. Recently, interest in semiempirical methods to...
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In: Physical Chemistry Chemical Physics, 2017, vol. 19, no. 31, p. 20919–20929
Methodological advents for the calculation of the multiplet energy levels arising from multiple-open-shell 2p53dn+1 electron configurations, with n = 0, 1, 2,… and 9, are presented. We use the Ligand-Field Density Functional Theory (LFDFT) program, which has been recently implemented in the Amsterdam Density Functional (ADF) program package. The methodology consists of calculating the...
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In: Journal of Molecular Modeling, 2017, vol. 23, no. 8, p. 243
The ligand field density functional theory (LFDFT) algorithm is extended to treat the electronic structure and properties of systems with three-open-shell electron configurations, exemplified in this work by the calculation of the core and semi-core 1s, 2s, and 3s one-electron excitations in compounds containing transition metal ions. The work presents a model to non-empirically resolve the...
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In: Physical Chemistry Chemical Physics, 2016, vol. 18, no. 28, p. 19020–19031
Ligand field density functional theory (LFDFT) calculations have been used to model the uranium M4,5, N4,5 and O4,5-edge X-ray absorption near edge structure (XANES) in UO₂, characterized by the promotion of one electron from the core and the semi-core 3d, 4d and 5d orbitals of U⁴⁺ to the valence 5f. The model describes the procedure to resolve...
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In: Inorganic Chemistry, 2015, vol. 54, no. 17, p. 8319–8326
The most efficient way to provide domestic lighting nowadays is by light-emitting diodes (LEDs) technology combined with phosphors shifting the blue and UV emission toward a desirable sunlight spectrum. A route in the quest for warm-white light goes toward the discovery and tuning of the lanthanide-based phosphors, a difficult task, in experimental and technical respects. A proper theoretical...
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In: Physical Chemistry Chemical Physics, 2015, vol. 17, no. 28, p. 18547–18557
Ligand field density functional theory (LFDFT) is a methodology consisting of non-standard handling of DFT calculations and post-computation analysis, emulating the ligand field parameters in a non-empirical way. Recently, the procedure was extended for two-open-shell systems, with relevance for inter-shell transitions in lanthanides, of utmost importance in understanding the optical and magnetic...
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In: Molecular Physics, 2015, vol. 113, no. 13-14, p. 1712-1727
A series of computational experiments performed with various methods belonging to wave-function and density functional theories approaches the issue of bonding regime and exchange coupling in the title compounds. Gd₂@C₈₀ is computed with a very weak exchange coupling, the sign depending on the method, while Gd₂@C₇₉N has resulted with a strong coupling and ferromagnetic ground...
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In: Inorganic Chemistry, 2015, vol. 54, no. 11, p. 5504–5511
Single crystals of uranium(IV)-containing A₂USi₆O₁₅ (A = K, Rb) were grown using the flux growth method. The two compounds crystallize in a new structure type related to Cs₂USi₆O₁₅. K₂USi₆O₁₅ exhibits an interesting crystal-to-crystal transition, which is accompanied by an intense color change. Magnetic properties are reported for A₂USi₆O₁₅ and differ from other...
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In: Physical Chemistry Chemical Physics, 2015, vol. 17, no. 14, p. 9116–9125
We present a theoretical work detailing the electronic structure and the optical properties of (PrF₈)⁵⁻ embedded in LiYF₄, complementing the insight with data that are not available by experimental line. The local distortions due to the embedding of the lanthanide ion in the sites occupied in the periodic lattice by smaller yttrium centres, not detectable in regular X-ray analyses, are...
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In: Chemical Physics Letters, 2015, vol. 622, p. 120–123
The theoretical rationalization of the open-shell 4f and 5d configuration of Eu²⁺ is by far not trivial because it involves a non-standard version of ligand field theory, based on a two-shell Hamiltonian. Here we present our methodology based on ligand field theory, taking the system CsCaBr₃:Eu²⁺ as a case study with an octahedral coordination sphere of Eu²⁺. The ligand field,...
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