Search results for " topological analysis"

showing 6 items of 6 documents

A Bader’s topological approach for the investigation of the high pressure stability field of the Mg-perovskite phase

2014

Bader topological analysis perovskite phase transitionSettore GEO/06 - MineralogiaSettore CHIM/02 - Chimica Fisica
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Pressure stability field of Mg-perovskite under deep mantle conditions: A topological approach based on Bader's analysis coupled with catastrophe the…

2019

Abstract The pressure stability field of the Mg-perovskite phase was investigated by characterizing the evolution of the electron arrangement in the crystal. Ab initio calculations of the perovskite structures in the range 0–185 GPa were performed at the HF/DFT (Hartree-Fock/Density Functional Theory) exchange–correlation terms level. The electron densities, calculated throughout the ab-initio wave functions, were analysed by means of the Bader's theory, coupled with Thom's catastrophe theory. To the best of our knowledge the approach is used for the first time. The topological results show the occurrence of two topological anomalies at P~20 GPa and P~110 GPa which delineate the pressure ra…

Materials Chemistry2506 Metals and AlloysMaterials scienceBader analysisAb initioSurfaces Coatings and FilmCritical pointsCeramics and Composite02 engineering and technologyElectronD’’ regionPerovskiteTopology01 natural sciencesCritical pointPhysics::GeophysicsFock spaceCoatings and FilmsCondensed Matter::Materials ScienceAb initio quantum chemistry methods0103 physical sciencesElectronicMaterials ChemistryOptical and Magnetic MaterialsAb initio; Bader analysis; Catastrophe theory; Critical points; Deep mantle; D’’ region; HF/DFT; High pressure; Perovskite; Topological analysis; Electronic Optical and Magnetic Materials; Ceramics and Composites; Process Chemistry and Technology; Surfaces Coatings and Films; Materials Chemistry2506 Metals and AlloysWave function010302 applied physicsCatastrophe theoryElectronic Optical and Magnetic MaterialProcess Chemistry and TechnologyHartree021001 nanoscience & nanotechnologyHF/DFTSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsSurfacesTopological analysiHigh pressureAb initioCeramics and CompositesDensity functional theoryDeep mantleCatastrophe theory0210 nano-technologyTopological analysisBader analysiCeramics International
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ADSORPTION OF WATER MOLECULES ONTO 1:1 DIOCTAHEDRAL CLAY MINERALS: A BADER'S TOPOLOGICAL ANALYSIS OF THE AB-INITIO ELECTRON DENSITIES

2011

ab-initioBader's topological analysiskaoliniteadsorptiondickite
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Characterization of the pressure induced Ringwoodite toMg-perovskite and Mg-wüstite phase transition by Catastrophe Theory

2010

Bader’s topological analysis Catastrophe Theory ab initio critical points
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The pressure-induced ringwoodite to Mg-perovskite and periclase post-spinel phase transition: a Bader’s topological analysis of the ab initio electro…

2011

In order to characterize the pressure-induced decomposition of ringwoodite (c-Mg2SiO4), the topological analysis of the electron density q(r), based upon the theory of atoms in molecules (AIM) developed by Bader in the framework of the catastrophe theory, has been performed. Calculations have been carried out by means of the ab initio CRYSTAL09 code at the HF/DFT level, using Hamiltonians based on the Becke- LYP scheme containing hybrid Hartree– Fock/density functional exchange–correlation terms. The equation of state at 0 K has been constructed for the three phases involved in the post-spinel phase transition (ringwoodite -> Mg-perovskite + periclase) occurring at the transition zone–lower…

Bader’s topological analysisElectron densityEquation of statePhase transitionRingwoodite Post-spinel phase transition Bader’s topological analysis Ab initio Catastrophe theory Critical pointsChemistryCatastrophe theoryAtoms in moleculesRingwooditeAb initioCritical pointsHartreeengineering.materialTopologyRingwoodite; Post-spinel phase transition; Bader’s topological analysis; Ab initio; Catastrophe theory; Critical pointsPost-spinel phase transitionRingwooditeGeochemistry and PetrologyBader’s topological analysiAb initioengineeringGeneral Materials SciencePerovskite (structure)
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Bader's analysis of the electron density in the Pbca enstatite - Pbcn protoenstatite phase transition

2011

The Bader’s topological analysis of the electron density obtained via ab initio quantum mechanical simulation at Hartree–Fock and DFT level has been performed for experimentally in situ heated structures of enstatite–protoenstatite MgSiO 3 . The measurements have been performed in the temperature range 1200–1400 K. The work was aimed at characterizing both the evolution of the electron arrangement in the crystal and that of the crystal-structure at the enstatite–protoenstatite phase transition in terms of topology of the electron density, with particular care about the Mg–O and the O–O bonds. The observed breaking of some chemical bonds with increasing temperature and/or due to the phase tr…

Phase transitionElectron densityBader’s topological analysis Catastrophe Theory ab initio reconstructive phase transition critical pointsChemical bondCondensed matter physicsGeochemistry and PetrologyChemistryPhase (matter)Atoms in moleculesAb initioElectronMolecular physicsTopology (chemistry)European Journal of Mineralogy
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