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Université de Fribourg

DFT investigation of methane metathesis with L2AnCH3 actinide complexes catalysts (L = Cl, Cp, Cp*; An = Ac, Th, Pa, U, Np, Pu)

Talbi-Ingrachen, Fazia ; Talbi, Fatiha ; Kias, Farida ; Elkechai, Aziz ; Boucekkine, Abdou ; Daul, Claude

In: Computational and Theoretical Chemistry, 2018, vol. 1138, p. 123–134

In order to understand the catalytic activity of the actinide complexes L2AnCH3 (An = Ac, Th, Pa, U, Np and Pu; L = Cl, Cp and Cp∗) towards the activation of the CH bond of methane, relativistic ZORA/DFT investigations have been carried out. The results obtained from Linear Transit (LT) and Intrinsic Reaction Coordinate (IRC) calculations show that the mechanism involved in these...

Université de Fribourg

Photoluminescence properties of Yb²⁺ ions doped in the perovskites CsCaX₃ and CsSrX₃ (X = Cl, Br, and I) – a comparative study

Suta, Markus ; Urland, Werner ; Daul, Claude ; Wickleder, Claudia

In: Physical Chemistry Chemical Physics, 2016, vol. 18, no. 19, p. 13196–13208

The Yb²⁺-doped perovskite derivatives CsMX₃ (M = Ca and Sr; X = Cl, Br, and I) are ideal systems for obtaining a detailed insight into the structure–luminescence relationship of divalent lanthanides. The investigation of the respective photoluminescence properties yielded two emission bands in the violet and blue spectral range for all compounds, which are assigned to the spin-allowed...

Université de Fribourg

Computational analysis of tris(1,2-ethanediamine) cobalt(III) complex ion : calculation of the ⁵⁹Co shielding tensor using LF-DFT

Senn, Florian ; Zlatar, Matija ; Gruden-Pavlovic, Maja ; Daul, Claude

In: Monatshefte für Chemie - Chemical Monthly : an International Journal of Chemistry, 2011, vol. 142, no. 6, p. 593-597

The ligand-field density functional theory (LF-DFT) approach is employed for calculations of the ⁵⁹Co nuclear magnetic resonance (NMR) shielding tensor of all four diastereoisomers (λλλ, λλδ, λδδ, and δδδ) of tris(1,2-ethanediamine) cobalt(III) complex ion, [Co(en)₃]³⁺. The obtained values split into two groups according to the point group of the diastereoisomers. The...

Université de Fribourg

Tailoring the optical properties of lanthanide phosphors: prediction and characterization of the luminescence of Pr3+-doped LiYF4

Ramanantoanina, Harry ; Urland, Werner ; Herden, Benjamin ; Cimpoesu, Fanica ; Daul, Claude

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...

Université de Fribourg

Calculation of the 4f¹ → 4f⁰5d¹ transitions in Ce³⁺-doped systems by Ligand Field Density Functional Theory

Ramanantoanina, Harry ; Urland, Werner ; García-Fuente, Amador ; Cimpoesu, Fanica ; Daul, Claude

In: Chemical Physics Letters, 2013, vol. 588, p. 260–266

We present a recipe for the calculation of the optical properties of Ce³⁺-doped systems. The model implies the use of ligand field phenomenology in conjunction with Density Functional Theory (DFT). The particular procedures enable the reliable prediction of the 4f¹ → 4f⁰5d¹ transitions in Cs₂NaYCl₆:Ce³⁺. The analysis of the doping of Ce³⁺ into the host is accomplished by band...

Université de Fribourg

Ligand field density functional theory for the prediction of future domestic lighting

Ramanantoanina, Harry ; Urland, Werner ; García-Fuente, Amador ; Cimpoesu, Fanica ; Daul, Claude

In: Physical Chemistry Chemical Physics, 2014, vol. 16, no. 28, p. 14625–14634

We deal with the computational determination of the electronic structure and properties of lanthanide ions in complexes and extended structures having open-shell f and d configurations. Particularly, we present conceptual and methodological issues based on Density Functional Theory (DFT) enabling the reliable calculation and description of the f → d transitions in lanthanide doped phosphors. We...

Université de Fribourg

The angular overlap model extended for two-open-shell f and d electrons

Ramanantoanina, Harry ; Urland, Werner ; Cimpoesu, Fanica ; Daul, Claude

In: Physical Chemistry Chemical Physics, 2014, vol. 16, no. 24, p. 12282–12290

We discuss the applicability of the Angular Overlap Model (AOM) to evaluate the electronic structure of lanthanide compounds, which are currently the subject of incredible interest in the field of luminescent materials. The functioning of phosphors is well established by the f–d transitions, which requires the investigation of both the ground 4fn and excited 4fn−15d1 electron configurations...

Université de Fribourg

Prospecting lighting applications with ligand field tools and density functional theory: a first-principles account of the 4f⁷–4f⁶5d¹ Luminescence of CsMgBr₃:Eu²⁺

Ramanantoanina, Harry ; Cimpoesu, Fanica ; Göttel, Christian ; Sahnoun, Mohammed ; Herden, Benjamin ; Suta, Markus ; Wickleder, Claudia ; Urland, Werner ; Daul, Claude

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...

Université de Fribourg

Ligand field density functional theory calculation of the 4f² → 4f¹5d¹ transitions in the quantum cutter Cs₂KYF₆:Pr³⁺

Ramanantoanina, Harry ; Urland, Werner ; Cimpoesu, Fanica ; Daul, Claude

In: Physical Chemistry Chemical Physics, 2013, vol. 15, no. 33, p. 13902–13910

Herein we present a Ligand Field Density Functional Theory (LFDFT) based methodology for the analysis of the 4fⁿ → 4fⁿ⁻¹5d¹ transitions in rare earth compounds and apply it for the characterization of the 4f² → 4f¹5d¹ transitions in the quantum cutter Cs₂KYF₆:Pr³⁺ with the elpasolite structure type. The methodological advances are relevant for the analysis and prospection of...