Relative energies of surface and defect states: ab initio calculations for the MgO (001) surface

Sushko, Peter V.; Shluger, Alexander L.; Catlow, C. Richard A.

doi:10.1016/s0039-6028(00)00290-9

Cited by 340 publications

(344 citation statements)

References 42 publications

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“…The positions of the valence band, conduction band, and F and F + impurity levels of the MgO surface have been determined recently. 57 The surface valence band lies 6.7 eV below the vacuum; an F center gives rise to a level about 3.7 eV below the vacuum. The Fermi level of a metal is usually around 4.5-5 eV; thus, if the MgO film is in contact with a metal substrate the F centers will release an electron to the metal conduction band with formation of an F + center.…”

Section: Discussionmentioning

confidence: 99%

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

et al. 2001

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CO adsorption on Pd atoms deposited on MgO(100) thin films has been studied by means of thermal desorption (TDS) and Fourier transform infrared (FTIR) spectroscopies. CO desorbs from the adsorbed Pd atoms at a temperature of about 250 K, which corresponds to a binding energy, E b , of about 0.7 ( 0.1 eV. FTIR spectra suggest that at saturation two different sites for CO adsorption exist on a single Pd atom. The vibrational frequency of the most stable, singly adsorbed CO molecule is 2055 cm -1 . Density functional cluster model calculations have been used to model possible defect sites at the MgO surface where the Pd atoms are likely to be adsorbed. CO/Pd complexes located at regular or low-coordinated O anions of the surface exhibit considerably stronger binding energies, E b ) 2-2.5 eV, and larger vibrational shifts than were observed in the experiment. CO/Pd complexes located at oxygen vacancies (F or F + centers) are characterized by much smaller binding energies, E b ) 0.5 ( 0.2 or 0.7 ( 0.2 eV, which are in agreement with the experimental value. CO/Pd complexes located at the paramagnetic F + centers show vibrational frequencies in closest agreement with the experimental data. These comparisons therefore suggest that the Pd atoms are mainly adsorbed at oxygen vacancies.

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Section: Discussionmentioning

confidence: 99%

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

et al. 2001

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“…Consequently, engineering protocols that aim at the reproducible adjustment of color and emission intensity can be developed. In previous work, we have shown how nanocrystalline MgO exhibits particle-size-dependent absorption and luminescence properties [9] which are connected to low-coordinated sites at the surface such as corners and edges [10][11][12]. We have also shown how doping with the higher group two metals Ca, Sr, and Ba leads to a red-shift in excitation and luminescence energies [13][14][15][16].…”

Section: Introductionmentioning

confidence: 88%

“…The forces acting on all ions are then calculated, and the geometry of the entire system is optimized self-consistently using the BFGS algorithm (e.g., see Refs. [11,31] for details). The main advantage of this approach is that it allows quantum mechanical treatment of local features in large, complex, and non-periodic nanostructures.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…They are cheap, widely available, non-toxic, and highly stable. The luminescence in these materials has a surface origin, therefore as particle size is reduced quantum yield is improved, while multiple scattering is minimized [9][10][11][12]. AEO can be prepared as highly dispersed solids via gas-phase synthesis and, thus, in the absence of solvents or surface groups that may affect the surface electronic structure in a less controllable way.…”

Section: Introductionmentioning

confidence: 99%

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Surface-specific visible light luminescence from composite metal oxide nanocrystals

et al. 2015

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Low-coordinated surface elements on metal oxide nanoparticles represent the basis for a new concept of luminescent nanoparticles made of abundant, non-toxic, and thermally stable materials. This combined experimental and theoretical study describes the generation and stability of Ba-doped MgO nanoparticle surfaces and their optical absorption and luminescence dependence on Ba loading. It is demonstrated that the vapor phase growth process employed here represents a particularly robust synthesis approach for particle powders with reproducibly adjustable photoluminescence emission properties in the range between blue and yellow light. Moreover, this indepth characterization also provides an understanding of the electronic and optical characteristics of this nanoparticulate material with a so far unnoticed potential for solidstate light applications that are based on down conversion of UV light.

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“…The described ideology was implemented in the GUESS computer code and tested for several systems [5][6][7]. Apart from ab initio results reported in this work a number of calculations were performed classically with pair potentials.…”

Section: Calculation Detailsmentioning

confidence: 99%

Optical properties and transformation mechanism of oxygen centres and their aggregates in CaF ₂ crystals

Mysovsky

Раджабов

Reichling

et al. 2005

phys. stat. sol. (c)

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Oxygen-vacancy dipoles and dimers in CaF 2 crystals have been studied ab initio at DFT level and with the shell model using pair potentials. The calculated dipole reorientation barrier is 0.64 eV and the activation energy for diffusion of the dipoles is 1.61 eV. Optical absorption of O 2--V A dipole have been calculated with TD DFT and identified with experimental absorption bands, which appeared to have complex structure. The photodissociation mechanism of the dipole is discussed. Several configurations of the dimer (O 2--V A ) 2 were calculated. The association energy for the most favourable one is 0.48 eV.

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Relative energies of surface and defect states: ab initio calculations for the MgO (001) surface

Cited by 340 publications

References 42 publications

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

Surface-specific visible light luminescence from composite metal oxide nanocrystals

Optical properties and transformation mechanism of oxygen centres and their aggregates in CaF ₂ crystals

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Relative energies of surface and defect states: ab initio calculations for the MgO (001) surface

Cited by 340 publications

References 42 publications

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

Identification of Defect Sites on MgO(100) Thin Films by Decoration with Pd Atoms and Studying CO Adsorption Properties

Surface-specific visible light luminescence from composite metal oxide nanocrystals

Optical properties and transformation mechanism of oxygen centres and their aggregates in CaF 2 crystals

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Product

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Optical properties and transformation mechanism of oxygen centres and their aggregates in CaF ₂ crystals