Search results for "iTED"

showing 10 items of 2408 documents

Cathodoluminescence and IR absorption of oxygen deficient silica – influence of hydrogen treatment

1999

Abstract The cathodoluminescence (CL) and IR absorption of silica samples with normal stoichiometry as well as with an extremely high level of oxygen deficit were studied. Additionally, some samples have been treated in hydrogen at 800°C. Crystalline quartz was used for reference measurements and the CL data have been compared with those of X-ray excited luminescence (XL). The luminescence spectra of silica have a band at 1.85 eV due to non-bridging oxygens and the two bands at 2.7 and 4.4 eV due to twofold-coordinated silicons. The energetic yield for CL is about 0.1%, for XL it approaches 0.15%. Cathodoluminescence of quartz at temperatures >130 K exhibits the self-trapped exciton lumines…

Nuclear and High Energy PhysicsRadiationMaterials scienceSiliconAbsorption spectroscopyHydrogenChemistryExcitonAnalytical chemistryInfrared spectroscopychemistry.chemical_elementCathodoluminescencePhotochemistryCondensed Matter PhysicsOxygenElectronic Optical and Magnetic MaterialsExcited stateMaterials ChemistryCeramics and CompositesGeneral Materials ScienceLuminescenceStoichiometryJournal of Non-Crystalline Solids
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Optical properties of oxygen-deficiency related centers in amorphous SiO 2 investigated by synchrotron radiation

2002

We report an investigation of the photoluminescence activity at 4.4 v eV in g -irradiated silica under UV and vacuum-UV excitation by synchrotron radiation. Our results evidence two iso-energetic contributions which can be related to two oxygen-deficient centers variants: ODC(I) and ODC(II). The first, excited within the 7.6 v eV absorption, is detected only at low temperature and has a lifetime of about 2 v ns. The second exhibits two excitation maxima peaked at 5.0 and 6.8 v eV, its amplitude decreases by a factor 2 on increasing the temperature whereas its lifetime has a value of about 4 v ns. These features give new insights on the excitation pathway of the 4.4 v eV emission involving t…

Nuclear and High Energy PhysicsRadiationPhotoluminescenceChemistryAnalytical chemistrySynchrotron radiationCondensed Matter PhysicsAmorphous solidAmplitudeNuclear magnetic resonanceExcited stateGeneral Materials ScienceIrradiationAbsorption (electromagnetic radiation)ExcitationRadiation Effects and Defects in Solids
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Pulsed electron beam excited transient absorption in SrTiO3

2002

Abstract Transient absorption (TA) spectra and optical density relaxation kinetics in SrTiO3 (STO), STO–Nb and STO–V were studied. The electron polaron free or bound at intrinsic defect is suggested to be responsible for the TA band at ∼1.4 eV observed in STO. The band peaking below 0.75 eV in STO–Nb is proposed to be from Nb4+. The electron center V3+ or electron polaron bound in the vicinity of V4+ is responsible for the absorption band at 1.0 eV in STO–V. The absorption from hole polarons is suggested to be in the range 1.8–2.3 eV. It is shown that TA in pure STO at room temperature decays due to electron–hole polaron recombination.

Nuclear and High Energy PhysicsRange (particle radiation)ChemistryAbsorption bandExcited stateUltrafast laser spectroscopyElectronAtomic physicsPolaronAbsorption (electromagnetic radiation)InstrumentationSpectral lineNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
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Self-trapped exciton luminescence in α-quartz

1994

Abstract It is shown that two differently oriented (perpendicular and parallel to the c axis) serf-trapped excitons (STE ⊥ and STE ∥ ) can be created in the range of the Urbach tail of the fundamental absorption of α-quartz. Below this tail no STE luminescence was found. The alkali ion centers, excited below the tail, give luminescence bands, which can be replaced by substituting alkali ions with Cu + ions. It is concluded that both STE ∥ and STE ⊥ are intrinsic.

Nuclear and High Energy PhysicsRange (particle radiation)ChemistryExcitonExcited stateAtomic physicsAbsorption (chemistry)Alkali metalLuminescenceInstrumentationBiexcitonIonNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
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Light-induced formation of metastable high-spin states in [Fe(mtz)6](CiO4)2

1988

[Fe(mtz)6](CiO4)2 (mtz=1-methyltetrazole) is a spin crossover compound with two different iron(II) lattice sites. Only one of them (lattice site A) shows thermally induced high spin (HS) ⇌ low spin (LS) spin transition. The LIESST effect (Light-Induced Excited Spin State Trapping) can be observed below 50 K. Complex molecules in B-sites remain in HS state at all temperatures. At ∼ 20 K irradiation with red light causes a partial conversion to another HS species, HS(C), with also practically infinite lifetime.

Nuclear and High Energy PhysicsSpin statesChemistrySpin transitionCondensed Matter PhysicsAtomic and Molecular Physics and OpticsLIESSTCrystallographySpin crossoverMetastabilityExcited stateMoleculeIrradiationPhysical and Theoretical ChemistryAtomic physicsHyperfine Interactions
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Collectivity in the light radon nuclei measured directly via Coulomb excitation

2015

Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z=82 and the neutron midshell at N=104. Purpose: Evidence for shape coexistence has been inferred from α-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of Rn202 and Rn…

Nuclear and High Energy Physics[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th]PopulationFOS: Physical sciencesCoulomb excitationshape coexistence01 natural sciences0103 physical sciencesNuclear Physics - ExperimentNeutroncollectivityNuclear Experiment (nucl-ex)010306 general physicseducationSpectroscopyNuclear ExperimentPhysicseducation.field_of_studyta114010308 nuclear & particles physicsGamma rayradonPhysique atomique et nucléaire3. Good healthRadonExcited stateQuadrupoleAtomic physicsGround state
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Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals

2015

We calculate properties of the ground and excited states of nuclei in the nobelium region for proton and neutron numbers of 92 <= Z <= 104 and 144 <= N <= 156, respectively. We use three different energy-density-functional (EDF) approaches, based on covariant, Skyrme, and Gogny functionals, each within two different parameter sets. A comparative analysis of the results obtained for odd-even mass staggerings, quasiparticle spectra, and moments of inertia allows us to identify single-particle and shell effects that are characteristic to these different models and to illustrate possible systematic uncertainties related to using the EDF modelling

Nuclear and High Energy Physics[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th]ProtonNuclear TheoryNuclear Theorychemistry.chemical_elementFOS: Physical sciences7. Clean energySpectral lineMoments of inertiaNuclear physicsNuclear Theory (nucl-th)NeutronCovariant transformationHeavy and superheavy nucleiPhysicsta114Odd–even mass staggeringMoment of inertiachemistryExcited stateQuasiparticleNobeliumQuasiparticle excitationsNuclear energy density functionalsNuclear masses
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Single-particle shell strengths near the doubly magic nucleus 56Ni and the 56Ni(p,γ)57Cu reaction rate in explosive astrophysical burning

2019

Angle-integrated cross-section measurements of the $^{56}$Ni(d,n) and (d,p) stripping reactions have been performed to determine the single-particle strengths of low-lying excited states in the mirror nuclei pair $^{57}$Cu-$^{57}$Ni situated adjacent to the doubly magic nucleus $^{56}$Ni. The reactions were studied in inverse kinematics utilizing a beam of radioactive $^{56}$Ni ions in conjunction with the GRETINA $\gamma$-array. Spectroscopic factors are compared with new shell-model calculations using a full $pf$ model space with the GPFX1A Hamiltonian for the isospin-conserving strong interaction plus Coulomb and charge-dependent Hamiltonians. These results were used to set new constrain…

Nuclear and High Energy Physicsastro-ph.SRNuclear TheoryExplosive materialnucl-thStrong interactionnucl-ex01 natural sciencesIonReaction ratesymbols.namesake0103 physical sciencesCoulombMirror nuclei010306 general physicsNuclear ExperimentNuclear ExperimentPhysicsradioactive beams010308 nuclear & particles physicsshell modellcsh:QC1-999Astrophysics - Solar and Stellar AstrophysicsExcited statesymbolsX-ray burststransfer reactionsAtomic physicsHamiltonian (quantum mechanics)ydinfysiikkalcsh:PhysicsPhysics Letters B
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Selective detection of 13C by laser photodetachment mass spectrometry

2008

Abstract In this paper, we demonstrate how laser photodetachment mass spectrometry (LPMS) can be used to selectively detect 13C− ions in the presence of 12C− ions in a low energy ion beam. An isotopically enriched beam of carbon ions consisting of equal amounts of 13C− and 12C− ions was extracted from an ion source. The ions interacted with a laser beam in a collinear geometry over a distance of 70 cm. Residual atoms produced in the photodetachment process were detected in a neutral particle detector placed downstream of the collinear interaction region. By making use of the Doppler effect we were able to selectively photodetach 13C− ions. The number of detected 13C atoms was 13 times large…

Nuclear and High Energy Physicseducation.field_of_studyIon beamChemistryPopulationLaserMass spectrometryCharged particleIon sourcelaw.inventionIonPhysics::Plasma PhysicslawExcited statePhysics::Atomic PhysicsAtomic physicseducationInstrumentationNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
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Mirror energy differences above the 0f7/2 shell: First γ-ray spectroscopy of the Tz = −2 nucleus 56Zn

2021

5 pags., 4 figs.

Nuclear and High Energy Physicssinkki (metallit)QC1-999Nuclear Theory01 natural sciencesnucleon removalmirror nuclei0103 physical sciencesSubatomic Physicsmedicine010306 general physicsSpectroscopyradioactive ion beamsNuclear ExperimentNucleonsPhysics[PHYS]Physics [physics]isotoopitValence (chemistry)Isovector010308 nuclear & particles physicsYrastPhysicsFísicaSymmetry Breakingmedicine.anatomical_structureisospin symmetryshell-model calculationsExcited stateEnergy DifferenceAtomic physicsMultipole expansionydinfysiikkaNucleusBeam (structure)
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