Université de Fribourg

Electronic fine structure calculation of metal complexes with three-open-shell s, d, and p configurations

Ramanantoanina, Harry ; Daul, Claude

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...

Université de Fribourg

Core electron excitations in U⁴⁺: modelling of the nd¹⁰5f² → nd⁹5f³ transitions with n = 3, 4 and 5 by ligand field tools and density functional theory

Ramanantoanina, Harry ; Kuri, Goutam ; Daul, Claude ; Bertsch, Johannes

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...

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

Development and applications of the LFDFT: the non-empirical account of ligand field and the simulation of the f–d transitions by density functional theory

Ramanantoanina, Harry ; Sahnoun, Mohammed ; Barbiero, Andrea ; Ferbinteanu, Marilena ; Cimpoesu, Fanica

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...

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

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

General treatment of the multimode Jahn–Teller effect: study of fullerene cations

Ramanantoanina, Harry ; Zlatar, Matija ; García-Fernández, Pablo ; Daul, Claude A. ; Gruden-Pavlović, Maja

In: Physical Chemistry Chemical Physics, 2013, vol. 15, no. 4, p. 1252-1259

A general model for the analysis of the Adiabatic Potential Energy Surfaces (APES) of the molecules that are subject to the multimode Jahn–Teller effect is presented. The method utilizes the information obtained by DFT calculations on a distorted stationary point on the APES. The essence of the model is to express the distortion along a model minimal energy path called Intrinsic Distortion Path...

Université de Fribourg

Density functional theory study of the multimode Jahn-Teller problem in the fullerene anion

Ramanantoanina, Harry ; Gruden-Pavlović, Maja ; Zlatar, Matija ; Daul, Claude A.

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

The fullerene anion, C₆₀⁻, within the Ih point group, is a spherical molecule subject to the T ⊗ h Jahn–Teller (JT) distortion. The descent in symmetry goes to the three epikernel subgroups, namely D5d, D3d, and D2h. The last one completely removes the electronic...