Search results for "ddc:54"

showing 10 items of 218 documents

Metal-Polyhydride Molecules Are Compact Inside a Fullerene Cage.

2015

Quantum chemical calculations show that metal−hydride molecules are more compact when they are placed inside a fullerene cage than when they are isolated molecules. The metal−hydrogen bond distance in ZrH4 becomes 0.15 A shorter when it is placed inside a C60 cage. Metal−polyhydride molecules with a large number of H atoms such as ScH15 and ZrH16, which are not bound as isolated molecules, are predicted to be bound inside a fullerene cage. It is also shown that two TiH16 clusters are bound inside a bicapped (9,0) carbon nanotube. Possible ways to make metal−hydrides inside C60 and nanotubes are suggested.

Quantum chemicalFullereneChemistryCarbon nanotubeComputer Science Applicationslaw.inventionMetalBond lengthCondensed Matter::Materials ScienceChemical physicsComputational chemistrylawvisual_artddc:540visual_art.visual_art_mediumPhysics::Atomic and Molecular ClustersMoleculePhysical and Theoretical ChemistryPhysics::Chemical PhysicsCageJournal of chemical theory and computation
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A theoretical study of the gas-phase chemi-ionization reaction between uranium and oxygen atoms

2005

The U+O chemi-ionization reaction has been investigated by quantum chemical methods. Potential-energy curves have been calculated for several electronic states of UO and UO+. Comparison with the available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemi-ionization reaction U+O -> UO++e(-) is proposed. The U+O and Sm+O chemi-ionization reactions are the first two metal-plus-oxidant chemi-ionization reactions to be studied theoretically in this way.

Quantum chemicalMolecular electronic statesChemistryGeneral Physics and Astronomychemistry.chemical_elementUraniumOxygenElectronic statesGas phaseOxygenAtom-atom reactionsAssociative ionisationOxygen atomPotential energy surfacesIonizationddc:540Reaction kinetics theoryPhysics::Atomic and Molecular ClustersUraniumPhysical chemistryPhysics::Atomic PhysicsPhysical and Theoretical ChemistryNuclear ExperimentChain reactionUranium compoundsThe Journal of Chemical Physics
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A search for new physics in dijet mass and angular distributions in pp collisions at [subscript √s=7] TeV measured with the ATLAS detector

2011

A search for new interactions and resonances produced in LHC proton–proton (pp) collisions at a centre-of-mass energy ps = 7 TeV was performed with the ATLAS detector. Using a dataset with an integrated luminosity of 36 pb−1, dijet mass and angular distributions were measured up to dijet masses of 3.5 TeV and were found to be in good agreement with Standard Model predictions. This analysis sets limits at 95% CL on various models for new physics: an excited quark is excluded for mass between 0.60 and 2.64 TeV, an axigluon hypothesis is excluded for axigluon masses between 0.60 and 2.10 TeV and quantum black holes are excluded in models with six extra space–time dimensions for quantum gravity…

QuarkParticle physicsChiral ColorCiências Naturais::Ciências FísicasPhysics beyond the Standard ModelAstrophysics::High Energy Astrophysical Phenomena:Ciências Físicas [Ciências Naturais]General Physics and AstronomyFOS: Physical sciencesddc:500.2dijet; mass; pp collisionts; ATLAS detector5307. Clean energy01 natural sciencesStandard ModelHigh Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)Atlas (anatomy)Chiral color0103 physical sciencesmedicine[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]String resonance010306 general physicsPhysicsQuantum chromodynamicsLarge Hadron ColliderScience & Technology010308 nuclear & particles physicsParton DistributionsSettore FIS/01 - Fisica SperimentaleHigh Energy Physics::PhenomenologyFísicaHadron CollidersQCDmedicine.anatomical_structureExperimental High Energy Physicsddc:540ComputingMethodologies_DOCUMENTANDTEXTPROCESSINGQuarkFísica nuclearHigh Energy Physics::ExperimentParticle Physics - Experiment
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Diastereoselective Synthesis of Spiro[pyrazolone-4,3′-tetrahydrothiophenes] via a Sulfa-Michael/Aldol Domino Reaction

2016

Synthesis : journal of synthetic organic chemistry 48(23), 4091-4098(2016). doi:10.1055/s-0035-1562473

Reaction conditions010405 organic chemistryChemistryOrganic ChemistryPyrazolone010402 general chemistry54001 natural sciencesCombinatorial chemistryCatalysisDomino0104 chemical scienceschemistry.chemical_compoundCascade reactionAldol reactionYield (chemistry)ddc:540medicineOrganic chemistryTetrahydrothiophenemedicine.drug
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Disordered sodium alkoxides from powder data: crystal structures of sodium ethoxide, propoxide, butoxide and pentoxide, and some of their solvates

2021

The crystal structures of NaOEt, NaOPr, NaOBu and NaOAm (Am = amyl = pentyl) were determined from powder data. These compounds crystallize in an anti-PbO structure in the space groups P 21 m and P4/nmm. Additionally, solvates with the composition NaOEt·2EtOH, NaOPr·2PrOH, NaOiPr·5iPrOH and NaOtAm·tAmOH were synthesized, and their structures were determined from single crystals. They form interesting chain structures of different compositions and topologies.

Recrystallization (geology)Sodiumchemistry.chemical_elementAlcoholCrystal structure010402 general chemistry010403 inorganic & nuclear chemistry01 natural scienceschemistry.chemical_compoundsolvateBärnighausen treeMaterials Chemistryddc:530Alkylchemistry.chemical_classificationSodium ethoxideChemistryMetals and AlloysResearch PapersAtomic and Molecular Physics and Optics0104 chemical sciencesElectronic Optical and Magnetic MaterialsisopropanolCrystallographysodium alkoxide548PXRDddc:540Alkoxidepowder dataPowder diffraction
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Synthesis of Polycyclic Indolines by Utilizing a Reduction/Cyclization Cascade Reaction

2021

European journal of organic chemistry 2021(45), 6097-6101 (2021). doi:10.1002/ejoc.202101191

Reduction (complexity)Acid catalysisCascade reactionChemistryddc:540Organic ChemistryPhysical and Theoretical Chemistry540Combinatorial chemistryEuropean Journal of Organic Chemistry
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The gas-phase chemiionization reaction between samarium and oxygen atoms: A theoretical study

2004

The Sm + O chemiionization reaction has been investigated theoretically using a method that allows for correlation and relativistic effects. Potential energy curves have been calculated for several electronic states of SmO and SmO+. Comparison with available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemiionization reaction Sm + O is proposed. The importance of spin–orbit coupling in the excited states of SmO, in allowing this chemiionization reaction to take place, has been revealed by these calculations. This paper shows the metal-plus-oxidant chemiionization reaction.

SamariumExcited statesGeneral Physics and Astronomychemistry.chemical_elementRelativistic correctionsPotential energyOxygenOxygenSamariumAtom-atom reactionsOxygen atomchemistryPotential energy surfacesExcited stateIonizationddc:540OxidationSpin-orbit interactionsPhysical and Theoretical ChemistryAtomic physicsRelativistic quantum chemistryChain reactionIonisationThe Journal of Chemical Physics
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First Study on Nihonium (Nh, Element 113) Chemistry at TASCA

2021

Frontiers in Chemistry 9, 753738 (2021). doi:10.3389/fchem.2021.753738

Shell (structure)Analytical chemistrychemistry.chemical_elementSuperheavy Elementselement 113gas phase chromatographyAtomic orbitalatomifysiikkaTASCAReactivity (chemistry)QD1-999Original ResearchIsotopeGeneral Chemistry540superheavy elementkemialliset ominaisuudetChemistryFleroviumsuperheavy elementsUnpaired electronchemistrynihoniumddc:540physical preseparationVolatility (chemistry)
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Background studies for acoustic neutrino detection at the South Pole

2011

The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method to measure the tiny flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS), deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed. Lacking an in-situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10 to …

SignalsTELESCOPEAbsolute noise levelAstrophysics::High Energy Astrophysical PhenomenaFluxFOS: Physical sciencesAstrophysics7. Clean energy01 natural sciencesIceCube Neutrino Observatorylaw.inventionIceCubeTelescopeAbsolute noise level; Acoustic neutrino detection; Neutrino flux limitNeutrino flux limitlawSIGNALS0103 physical sciencesWATERDetection theory010306 general physicsTelescopeInstrumentation and Methods for Astrophysics (astro-ph.IM)PhysicsAcoustic neutrino detector010308 nuclear & particles physicsDetectorAstrophysics::Instrumentation and Methods for AstrophysicsWaterAstronomy and AstrophysicsGeodesyAcoustic neutrino detectionNoiseNeutrino detectorPhysics and Astronomy13. Climate actionddc:540NeutrinoAstrophysics - Instrumentation and Methods for Astrophysics
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Correlations of the distribution of spin states in spin crossover compounds

1999

Abstract Short range correlations of the distribution of high spin (HS) and low spin (LS) states show up in thermal spin transition curves, decay curves of the light induced metastable HS state (LIESST state), and in structural features during the spin transitions. Correlations are due to short range interactions between the spin crossover molecules. Short range interactions may compete with omnipresent long range interactions and give rise to interesting spin transition phenomena. In this paper, the effect of correlations on the thermal spin transition in the mixed crystal system [Fe x Zn 1− x (pic) 3 ]Cl 2 ·EtOH (pic=picolylamine) is discussed. In particular the step in the thermal transi…

Spin statesCondensed matter physicsChemistrySpin transitionSpin crossoverLIESSTCorrelationInorganic ChemistrySpin crossoverLattice (order)Metastabilityddc:540Materials ChemistryMoleculeOrthorhombic crystal systemCondensed Matter::Strongly Correlated ElectronsPhysical and Theoretical ChemistryPhase transition
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