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Université de Fribourg

Indirect solvent assisted tautomerism in 4-substituted phthalimide 2-hydroxy-Schiff bases

Yordanov, Dancho ; Deneva, Vera ; Georgiev, Anton ; Crochet, Aurélien ; Fromm, Katharina M. ; Antonova, Liudmil

In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020, vol. 237, p. 118416

The paper presents the synthesis and characterization of two 4-substituted phthalimide 2-hydroxy-Schiff bases containing salicylic (4) and 2-hydroxy-1-naphthyl (5) moieties. The structural differences of 2-hydroxyaryl substituents, resulting in different enol/keto tautomeric behaviour, depending on the solvent environment were studied by absorption UV–Vis spectroscopy. Compound 5 is...

Université de Fribourg

Electronic structure and photoluminescence properties of Eu(η9-C9H9)2

Ramanantoanina, Harry ; Merzoud, Lynda ; Muya, Jules Tshishimbi ; Chermette, Henry ; Daul, Claude

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...

Consortium of Swiss Academic Libraries

Chemical Bonding in Molecules and Complexes Containing d-Elements Based on DFT

Atanasov, Mihail ; Daul, Claude A. ; Fowe, E. Penka

In: Monatshefte für Chemie / Chemical Monthly, 2005, vol. 136, no. 6, p. 925-963

Université de Fribourg

Measurement of the scalar third-order electric polarizability of the Cs ground state using coherent-population-trapping spectroscopy in Ramsey geometry

Robyr, Jean-Luc ; Knowles, Paul ; Weis, Antoine

In: Physical Review A, 2014, vol. 90, no. 1, p. 012505

The ac-Stark shift induced by blackbody radiation is a major source of systematic uncertainty in present-day cesium microwave frequency standards. The shift is parametrized in terms of a third-order electric polarizability α(3)0 that can be inferred from the static electric-field displacement of the clock transition resonance. In this paper, we report on an all-optical...

Université de Fribourg

A new mixed-ligand copper(II) complex of (E)-N′-(2-hydroxybenzylidene) acetohydrazide: Synthesis, characterization, NLO behavior, DFT calculation and biological activities

Ebrahimipour, S. Yousef ; Sheikhshoaie, Iran ; Crochet, Aurélien ; Khaleghi, Moj ; Fromm, Katharina M.

In: Journal of Molecular Structure, 2014, vol. 1072, p. 267–276

A tridentate hydrazone Schiff base ligand, (E)-N′-(2- hydroxybenzylidene)acetohydrazide [HL], and its mixed-ligand Cu(II) complex [CuL(phen)], have been synthesized and characterized by elemental analyses, FT-IR, molar conductivity, UV–Vis spectroscopy. The structure of the complex has been determined by X-ray diffraction. This complex has square pyramidal geometry and the positions...

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...