Ab initio study of F-centers in alkali halides

Hoya, J.; Laborde, Juan Martín; Richard, Diego; Rentería, M.

doi:10.1016/j.commatsci.2017.07.015

Cited by 12 publications

(10 citation statements)

References 28 publications

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“…Indeed, by contrast to the Gaussian shape of absorption bands caused by color centers (see e.g. Jenkins et al, 2000;Hoya et al, 2017), surface plasmon resonances exhibited by metallic nanoparticles give rise to Lorentzian-shaped absorption bands, as predicted by Mie theory (Kreibig and Vollmer, 1995;Seinen et al, 1994;Ruiz-Fuertes et al, 2019). A good fit of the main band is achieved by using a Lorentzian function peaking at 494 nm.…”

Section: Optical Absorption Spectra Of Villiaumitementioning

confidence: 96%

“…The two minor contributions at 328 nm and 414 nm have a Gaussian lineshape. The former corresponds to a F-center, widely investigated in synthetic NaF (Seifert et al, 1994;Tiwald et al, 2015;Hoya et al, 2017). The latter may be assigned to a R-center (Amenu- Kpodo and Neubert, 1965;Bryukvina and Martynovich, 2012;Bryukvina et al, 2018).…”

Section: Optical Absorption Spectra Of Villiaumitementioning

confidence: 99%

“…DOI: https://doi.org/10.2138/am-2021-7917. http://www.minsocam.org/ (Tiwald et al, 2015;Hoya et al, 2017) have shown that the absorption energy E a of the F-center (in eV) may be approximated by:…”

Section: Optical Absorption Spectra Of Villiaumitementioning

confidence: 99%

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Sodium nanoparticles in alkali halide minerals: Why is villiaumite red and halite blue?

Calas

Galoisy

Geisler

2021

American Mineralogist

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The presence of metal Na nanoparticles causes the bright, thermally unstable colors of villiaumite, NaF, and halite, NaCl. These nanoparticles have been suspected since a long time to be caused by external irradiation. Metal nanoparticles, often referred to as metal colloids, cause surface plasmon resonance effects, characterized by a single Lorentzian-shaped absorption band.The color of these minerals is due to metal Na nanoparticles of 2.5-3 nm. A key point is that the resonance wavelength, which corresponds to the maximum of the absorption band, is inversely related to the value of the refractive index of the embedding mineral. This causes the position of the main absorption band to be offset downwards by 140 nm in halite relative to villiaumite. As a consequence, the optical transmission window is shifted from the long to the short wavelength domain, explaining the color of blue halite and red villiaumite, respectively. Similar refractive This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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Section: Optical Absorption Spectra Of Villiaumitementioning

confidence: 96%

Section: Optical Absorption Spectra Of Villiaumitementioning

confidence: 99%

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Sodium nanoparticles in alkali halide minerals: Why is villiaumite red and halite blue?

Calas

Galoisy

Geisler

2021

American Mineralogist

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“…Compared to simple alkali halides, alkaline-earth halides, MgF 2 or LaF 3 [19,[28][29][30][31] and binary simple oxides such as MgO or Al 2 O 3 [18,19], the more complex electronic structure of oxide perovkites has important implications for the electronic structure of the corresponding F-type centers [18,19,22,24]. In ionic oxides, the ground state of the F center contains two electrons, which are well localized in vacancies, which leads to the appearance of energy levels in the band gap [19], while for perovskite oxides, the electronic structure of F-type defects has been the subject of long discussions [16-19, 22, 24].…”

Section: Introductionmentioning

confidence: 99%

First principles hybrid Hartree-Fock-DFT calculations of bulk and (001) surface F centers in oxide perovskites and alkaline-earth fluorides

Eglitis

Попов

Purans

et al. 2020

Low Temperature Physics

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We report the results of ab initio calculations and analysis of systematic trends for the F centers in the bulk and on the (001) surface in oxide perovskites, such as BaTiO 3 , SrTiO 3 , SrZrO 3 , and PbZrO 3 , with a corresponding comparison of the F centers in perovskites with those in alkaline earth metal fluorides (CaF 2 , BaF 2 , and SrF 2 ). It was found that in perovskites in both bulk F centers and those on their (001) surfaces, two nearest to the vacancy Ti or Zr atoms repel each other, while the next nearest O atoms relax towards the oxygen vacancy. It was also found that the obtained relaxations of atoms in the nearest neighborhood around the F center in ABO 3 perovskites are generally larger than in alkaline earth metal fluorides. The bulk and (001)-terminated surface F center ground states in BaTiO 3 , SrTiO 3 , and SrZrO 3 perovskites are located 0.23, 0.69, 1.12 eV, and 0.07, 0.25, 0.93 eV, respectively, below the conduction band bottom, indicating that the F center is a shallow donor. The vacancies in BaTiO 3 , SrZrO 3 , and PbZrO 3 are occupied with 1.103e, 1.25e, and 0.68e, respectively, whereas slightly smaller charges, only 1.052e, 1.10e, and 0.3e are localized inside the F center on the perovskite (001) surface. In contrast to the partly covalent ABO 3 perovskites, charge is well localized (around 80 %) inside the ionic CaF 2 , BaF 2 , and SrF 2 fluorine vacancy.

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“…A deep understanding of the optical properties of solids is impossible without a detailed knowledge of their electronic structure. The electronic processes in ionic crystals are considered on the basis of the approximate quantum-mechanical theory where the motion of electrons and nuclei is separated based on adiabatic Born-Oppenheimer approximation [33], [34]. One of the characteristics of the reflecting property of a nano-objects is the electronic density of states: the number of allowed electron (or hole) states per volume for a given energy [31].…”

Section: Introductionmentioning

confidence: 99%

Computer Simulations of the Band Structure and Density of States of the Linear Chains of NaCl Ions

Myasnikova

Istlyaup

Sergeyev

et al. 2019

Latvian Journal of Physics and Technical Sciences

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The paper presents the results of first-principles computer simulations of the band structure, the density of states, and the total energy of NaCl (NaCl, Na2Cl2, Na3Cl3, Na4Cl4, Na6Cl6) linear chains of atoms. Modelling of the specified characteristics is realised in the computer code Atomistix ToolKit combined with Virtual NanoLab. The total energy depends on the number of ions in the nanoobject under study, but practically does not depend on the geometric arrangement of ions.

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Ab initio study of F-centers in alkali halides

Cited by 12 publications

References 28 publications

Sodium nanoparticles in alkali halide minerals: Why is villiaumite red and halite blue?

Sodium nanoparticles in alkali halide minerals: Why is villiaumite red and halite blue?

First principles hybrid Hartree-Fock-DFT calculations of bulk and (001) surface F centers in oxide perovskites and alkaline-earth fluorides

Computer Simulations of the Band Structure and Density of States of the Linear Chains of NaCl Ions

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