Search results for "2ND-ROW ELEMENTS"

showing 3 items of 3 documents

The first example of cofacial bis(dipyrrins)

2016

International audience; Two series of cofacial bis(dipyrrins) were prepared and their photophysical properties as well as their bimolecular fluorescence quenching with C-60 were investigated. DFT and TDDFT computations were also performed as a modeling tool to address the nature of the fluorescence state and the possible inter-chromophore interactions. Clearly, there is no evidence for such interactions and the bimolecular quenching of fluorescence, in comparison with mono-dipyrrins, indicates that C-60-bis(dipyrrin) contacts occur from the outside of the "mouth" of the cofacial structure.

010402 general chemistryPhotochemistry01 natural sciences[ CHIM ] Chemical SciencesCatalysisTransition metalexcitation-energiesmolecular-orbital methodsorganometallic compoundsMaterials Chemistry[CHIM]Chemical Sciencessinglet energy transfersdensity-functional theoryvalence basis-setsGroup 2 organometallic chemistryQuenching (fluorescence)010405 organic chemistryChemistryGeneral ChemistryTime-dependent density functional theorytransition-metalsFluorescence0104 chemical scienceslight-harvesting systems2nd-row elementsDensity functional theoryextended basis-sets
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Cation Environment of BaCeO3−Based Protonic Conductors II: New Computational Models

2011

Quantum chemical calculations have been carried out to simulate Y-doped BaCeO(3) derivatives. Hartree-Fock energy functional was used to study octahedral site environments embedded in a Pmcn orthorhombic framework, showing local arrangement characterized by Ce-O-Ce, Ce-O-Y, and Y-O-Y (Z-O-Ξ) configurations and including or not hydrogen close to the moieties encompassing those configurations. The latter are, in fact, representative of - and, in our modeling approach, were treated as - local arrangements that could be found in Y:BaCeO(3)-doped materials. The geometrical optimizations performed on the structural models and a detailed orbital analysis of these systems allowed us to confirm and …

Phase transitionExtended X-ray absorption fine structureHydrogenShell (structure)2ND-ROW ELEMENTSchemistry.chemical_elementDOPED BARIUM CERATECrystal structureEXTENDED BASIS-SETSRELATIVISTIC EFFECTIVE POTENTIALSSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)MOLECULAR-ORBITAL METHODSchemistryOctahedronSettore CHIM/03 - Chimica Generale E InorganicaComputational chemistryChemical physicsPEROVSKITE OXIDESCRYSTAL-STRUCTURESPHASE-TRANSITIONSOrthorhombic crystal systemAB-INITIO PSEUDOPOTENTIALSPhysical and Theoretical ChemistryVALENCE BASIS-SETSEnergy functionalThe Journal of Physical Chemistry A
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Molecular structures of Se(SCH3)2 and Te(SCH3)2 using gas-phase electron diffraction and ab initio and DFT geometry optimisations

2005

The molecular structures of Se(SCH3)2 and Te(SCH3)2 were investigated using gas-phase electron diffraction (GED) and ab initio and DFT geometry optimisations. While parameters involving H atoms were refined using flexible restraints according to the SARACEN method, parameters that depended only on heavy atoms could be refined without restraints. The GED-determined geometric parameters (rh1) are: rSe-S 219.1(1), rS-C 183.2(1), rC-H 109.6(4) pm; S-Se-S 102.9(3), Se-S-C 100.6(2), S-C-H (mean) 107.4(5), S-Se-S-C 87.9(20), Se-S-C-H 178.8(19)° for Se(SCH3)2, and rTe-S 238.1(2), rS-C 184.1(3), rC-H 110.0(6) pm; S-Te-S 98.9(6), Te-S-C 99.7(4), S-C-H (mean) 109.2(9), S-Te-S-C 73.0(48), Te-S-C-H 180.…

MAIN-GROUP ELEMENTSCRYSTALLINE PHASESPopulationAb initioElectronsGeometrySulfidesATOMSInorganic ChemistryBI3RD-ROWMoleculeORBITAL METHODSPOLARIZATION FUNCTIONSSelenium CompoundseducationVALENCE BASIS-SETSConformational isomerismBasis seteducation.field_of_studyValence (chemistry)Molecular StructureChemistry2ND-ROW ELEMENTSCrystallographyMain group elementDENSITYExcited stateTelluriumDalton Transactions
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