Self-consistent electronic structures of CaO and BaO

Springborg, Michael; Taurian, Oscar E.

doi:10.1088/0022-3719/19/32/010

Cited by 37 publications

(17 citation statements)

References 14 publications

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“…The majority of available theoretical calculations predict a p-bandwidth value within 2-3 eV [9,11,12,13,14,15,16,17,5,18,52]. Our previous calculations [52] give a range from 2.61 to 2.88 eV, which is close to the present, raw LMTO result.…”

Section: P-bandsupporting

confidence: 85%

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Electronic band structure of calcium oxide

Bolorizadeh

Sashin

Kheifets³

et al. 2004

Journal of Electron Spectroscopy and Related Phenomena

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Abstract. We employed electron momentum spectroscopy (EMS) to measure the bulk electronic structure of calcium oxide. We extracted the electron momentum density (EMD), density of occupied states (DOS), band dispersions, bandwidths and intervalence bandgaps from the data. The results are compared with calculations based on the full potential linear muffin-tin orbital (FP-LMTO) approximation. While the bandwidths of 0.6 ± 0.2 eV and 1.2 ± 0.1 eV for the s-and p-bands, respectively, and their dispersions agree well with the LMTO calculation, the relative intensity of the two bands is at odds with the theory. The measured intervalence bandgap at the Γ-point of 16.5 ± 0.2 eV is larger by 2.1 eV than that from the LMTO calculation. The experimental bandwidth of the Ca 3p semi-core level of 0.7 ± 0.1 eV agrees with the LMTO prediction. The measured bandgap between this level and the s-band is 3.6 ± 0.2 eV. The Ca 3s-3p level splitting is in excellent agreement with the literature.

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Section: P-bandsupporting

confidence: 85%

“…A number of band structure calculations on CaO have been carried out by various theoretical approaches [8,9,10,11,12,13,14,15,16,17,18,19,20]. At the same time experimental data on the subject are quite limited.…”

Section: Introductionmentioning

confidence: 99%

Electronic band structure of calcium oxide

Bolorizadeh

Sashin

Kheifets³

et al. 2004

Journal of Electron Spectroscopy and Related Phenomena

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“…Substitution energies were calculated for each mode at the vertices of the polygon (points A to E, which run from maximum oxidizing to maximum reducing conditions) for three different iron environments: FeO (case 1), α-Fe 2 O 3 (case 2) and bcc bulk Fe (case 3). Table 2 compares the values for the cohesive energies, lattice parameters, energy gaps and magnetic moment per site calculated in this work with those taken from the literature [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] -no data were found for the gaps of tetragonal BaO 2 and TiO. In the context of this work, these data are relevant, since the defect energies are defined in terms of the respective chemical potentials, which depend on the cohesive energies.…”

Section: Defect Energies Calculationmentioning

confidence: 99%

First-principles study of neutral defects in Fe-doped cubic barium titanate

Meléndez

Zulueta

Leyet

2015

Ceramics International

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“…Los espectros UV-Vis-NIR de las muestras x=0,6 CE y CO que se muestran en la Figura 5,presentan (10)(11)(12)(13)(14). Esta banda produce una absorción en el azul y es la responsable de la intensificación del color amarillo.…”

Section: Ecopigmentos Cerámicos Verdes Y Amarillos De Pr 2 Mo 2 O 9 Dunclassified

Ecopigmentos cerámicos verdes y amarillos de Pr2Mo2O9 dopados con calcio obtenidos en presencia de mineralizadores y por coprecipitación química

Galindo¹,

Gargori²,

Llusar³

et al. 2011

Bol. Soc. Esp. Ceram. Vidr.

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En el presente trabajo se presenta la síntesis de disoluciones sólidas (Pr 2-x Ca x )Mo 2 O 9 vía cerámica, comprobándose la evolución cristalográfica y de coloración del verde al amarillo, al aumentar la cantidad de iones calcio (x) en la disolución sólida descrita en la literatura. Se ha estudiado el comportamiento al esmaltar plaquetas cerámicas con una frita de bicocción sin plomo, coloreada al 5% en peso del pigmento, la cual rinde colores amarillos suaves que no superan el valor de la coordenada cromática b*=19. La mineralización con NH 4 Cl, NaF y Na 2 SiF 6 de la composición (Pr 2-x Ca x )Mo 2 O 9 con x=0,1 e igual cantidad molar de halógenos (0,84 moles por peso fórmula), desarrolla un efecto estructural del ión fluoruro sobre la disolución sólida que no se traduce en una mejor coloración en el esmalte. La utilización de la coprecipitación amoniacal en la muestra x=0,6 produce una cristalización similar a su homóloga cerámica, pero con picos de difracción de rayos x más intensos y menos anchos, lo que indica una cristalización más regular y de mayor tamaño cristalino que se corrobora mediante la microscopia electrónica de barrido. Esta microestructura confiere coloraciones amarillas más intensas en las muestras en polvo y permite resistir mejor el ataque del vidriado, produciendo coloraciones amarillas significativamente superiores a las de las muestras cerámicas. Palabras clave: óxido doble de praseodimio y molibdeno, pigmento cerámico, mineralizadores, coprecipitación.Ecofriendly green and yellow ceramic pigments based on calcium-doped Pr 2 Mo 2 O 9 obtained by addition of mineralizers and chemical coprecipitation.In this paper the synthesis of (Pr 2-x Ca x )Mo 2 O 9 solid solutions by ceramic route is presented. Crystallography and colour evolution from green to yellow described on literature have been checked. When enamelled in a lead free double firing ceramic glaze, pigments produces light yellow colours not better than b*=19. Using NH 4 Cl, NaF and Na 2 SiF 6 as mineralizers in the (Pr 2-x Ca x )Mo 2 O 9 x=0,1 composition with the same molar addition of halogens (0.84 mols per formula weight), a structural effect of fluoride ion is observed but the yellow colour on enamelled samples do not improve. Finally, using an ammonia coprecipitation method in the x=0.6 sample, a similar crystallization to the homologous ceramic sample is detected, but x ray diffraction peaks are more intense and less wide, pointing to a more regular and higher crystal size crystallization which is checked by electronic scanning microscopy. This microstruture give more intense yellow coloured powders and improve their resistance against glaze, producing significantly best yellow colours than ceramic samples.Key words: praseodymium and molybdenum double oxide, ceramic pigment, mineralizers, coprecipitation. INTRODUCCIÓNEl amarillo es uno de los pigmentos más utilizados tanto en aplicaciones cerámicas, vidrio, plásticos o pinturas. Los sistemas habituales son el amarillo de vanadio en casiterita, el de vanadio en circona (1),...

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Self-consistent electronic structures of CaO and BaO

Cited by 37 publications

References 14 publications

Electronic band structure of calcium oxide

Electronic band structure of calcium oxide

First-principles study of neutral defects in Fe-doped cubic barium titanate

Ecopigmentos cerámicos verdes y amarillos de Pr<sub>2</sub>Mo<sub>2</sub>O<sub>9</sub> dopados con calcio obtenidos en presencia de mineralizadores y por coprecipitación química

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