Absorption spectra of poly-N-vinylcarbazole derivatives by experiment and simulation

Geometry molecular optimization and quantum chemical simulations of absorption spectra for newly synthesized poly-N-vinylcarbazole derivatives were performed using a semi-empirical approach. The studied polymers were modified by changing the positions of the carbazole group with respect to the polymer backbone. The absorption spectra were calculated for different numbers of PNVK monomers. A sufficient agreement between the calculated and experimentally measured spectra was observed. A change of the red shift absorption with respect to the blue shift was observed for cases when the number of monomers was higher than 4. The theoretical simulations indicate that this behavior is a consequence of the specific molecular structure of the considered molecules. The results demonstrate the potential of combined simulation and experimental studies in materials engineering and searching of new electro-luminescent materials

Electronic and optical properties of new synthesized TTF-based azine derivatives – Experimental and theoretical study

The synthesis and detailed characterization of two tetrathiafulvalene-appended azine derivatives, namely 2-([2,2′-bi(1,3-dithiolylidene)]-4-yl)-6-((2,4-dimethylphenyl)hydrazono) methyl)pyridine (L1) and 5-([2,2′-bi(1,3-dithiolylidene)]-4-yl)-2-((2,4-dimethylphenyl)hydrazono) methyl)pyridine (L2) are described. The crystal structure of ligand L2 indicates that the mentioned molecule is completely planar with the presence of a strong intramolecular N1 [single bond] H1⋯N3 hydrogen bonding. The quantum chemical calculations show that the intermolecular interaction in crystal structure does not affect the HOMO and LUMO orbitals present in isolated molecule. The optical properties of these ligands indicate the presence of intramolecular charge transfer band in the case of ligand L2 while the electrochemical behavior of the two compounds indicates that they are valuable candidates for the construction of crystalline radical cation salts

Magnetic and Electronic Properties of Selected Rare-Earth Chromium Germanides Compounds

The ternary rare-earth compounds exhibit interesting physical and structural properties. These structures changing composition and stoichiometry change drastically their magnetic properties. Some of them, based on chromium germanides were studied experimentally concerning their magnetic properties and up to our knowledge they were never studied theoretically explaining nature of their magnetic behaviour. In the presented work the nature and mechanism of the magnetic and electronic properties of rare-earth chromium germanides is presented. The magnetic and electronic properties of RCrGe₂ and $RCr_{0.3}Ge₂$ (R = Tb, Dy, Ho or Er) were investigated theoretically applying plane-wave density functional theory/Perdew-Burke-Ernzerhof methodology. The computational investigations were performed for the stoichiometric and nonstoichiometric crystal structure with the space group Cmcm. The stoichiometry of the rare-earth chromium germanides compounds has significant effect on the magnetic properties of the investigated material. The theoretical predictions are compared to the experimentally obtained results

EPR in functional structures based on doped (nano, meso)- porous silica and titanium dioxide

International audienc

Mesoporous Silica Functionalized by Cyclam-Metal Groups: Spectroscopic Studies and Numerical Modeling

International audienc

New Hybrid Materials Made from Dipolar Fe(II) Arylacetylide Complexes Exhibiting Temperature-Dependent Second Harmonic Generation Properties

International audienc

Nonstoichiometric defects and optical properties in LiNbO3

International audienc

Band structure treatment of the influence of nonstoichiometric defects on optical properties in LiNbO3

International audienc