Ergebnisse einschränken

Dokumententyp

Sprache

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

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 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...

Université de Fribourg

Benzo[1,2-b:4,5-b′]difuran-based sensitizers for dye-sensitized solar cells

Li, Hui ; Yi, Chenyi ; Moussi, Sofiane ; Liu, Shi-Xia ; Daul, Claude ; Grätzel, Michael ; Decurtins, Silvio

In: RSC Advances, 2013, vol. 3, no. 43, p. 19798–19801

Two BDF-based organic sensitizers, as first examples for their use in dye-sensitized solar cells, are prepared and characterized. They yield promising power conversion efficiencies of up to 5.5% and high open circuit voltages up to 0.82 V. This work demonstrates that the BDF chromophore acts as an effective donor in organic sensitizers.

Université de Fribourg

Spherical aromaticity of Jahn–Teller active fullerene ions

Perić, Marko ; Andjelković, Ljubica ; Zlatar, Matija ; Nikolić, Aleksandar S. ; Daul, Claude ; Gruden-Pavlović, Maja

In: Monatshefte für Chemie - Chemical Monthly, 2013, vol. 144, no. 6, p. 817–823

Density functional theory was applied to compute the nucleus-independent chemical shifts of fullerene (C₆₀), the fullerene ion C₆₀ ¹⁰⁺, and the Jahn–Teller active fullerene anion C₆₀ ⁻ and cation C₆₀ ⁺. Positioning a ³He nucleus inside the cage of each of these fullerene species facilitates investigations of the substantial differences among them, ³He NMR chemical...

Université de Fribourg

The choice of the exchange-correlation functional for the determination of the jahn–teller parameters by the density functional theory

Andjelković, Ljubica ; Gruden-Pavlović, Maja ; Daul, Claude ; Zlatar, Matija

In: International Journal of Quantum Chemistry, 2012, p. -

The Jahn–Teller (JT) parameters for small, aromatic, organic radicals, CnHn (n = 4–7), bis(cyclopentadienyl)cobalt(II) (cobaltocene), a sodium cluster (Na3), a silver cluster (Ag3), the hexaflurocuprate(II) ion ([CuF6]4−), and tris(acetylacetonato)manganese(III) ([Mn(acac)3]) have been evaluated by the means of the multideterminantal density functional theory using the most common...

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

Polytopal rearrangement of [Ni(acac)₂(py)]: A new square pyramid ⇄ trigonal bipyramid twist mechanism

Daul, Claude ; Niketic, Svetozar ; Rauzy, Cédrick ; Schläpfer, Carl-Wilhelm

In: Chemistry - A European Journal, 2004, vol. 10(3), p. 721-727

The interconversion mechanisms between three idealized polytopal forms (a square pyramid and two trigonal bipyramids) of [M(bidentate)₂(unidentate)] were investigated by an original combination of molecular mechanics (MM) and density functional theory (DFT) approaches. MM was used to model the mechanistic rearrangement path, and DFT to study selected points along this path. The test case was a...

Université de Fribourg

DFT study of mixed-valent Mn(II/III) hexacyanide clusters

Daul, Claude ; Rauzy, Cédrick ; Decurtins, Silvio ; Franz, Patrick ; Hauser, Andreas

In: International Journal of Quantum Chemistry, 2005, vol. 101, no. 6, p. 753-760

The cubic Prussian blue analogue Mn³[Mn(CN)₆]₂·15H₂O, which has the advantage of being transparent and magnetic (TN = 35 K) at the same time, has been investigated by density functional theory (DFT) calculations. The three-dimensional structure is built of MnII ions linked to MnIII ions by μ-bridging cyanides, to form a crystal structure,...