Adsorption geometry of OH adsorbed at<i>F</i>centers on a NaCl(100) surface

Malaske, U.; Pfnür, H.; Bäßler, M.; Weiss, Michael J.; Umbach, E.

doi:10.1103/physrevb.53.13115

Cited by 31 publications

(23 citation statements)

References 15 publications

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“…The electronic properties of the F center are well studied with a plethora of theoretical methods. − Its reactivity was explored for NaCl and KCl both in experiments − and theoretically using density functional theory (DFT) studies. ,,− It acts as a strong, local reduction site, and readily transfers the defect electron to a wide range of organic molecules. This makes it an interesting candidate for catalytic reactions.…”

Section: Introductionmentioning

confidence: 99%

Mobility of F Centers in Alkali Halides

Häfner

Bredow

2021

J. Phys. Chem. C

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The migration of F centers in alkali halides is important both for characterizing their chemical reactivity and as a benchmark for theoretical methods. In order to provide a solid basis for the assessment of theoretical methods, we reviewed the available experimental literature on the migration of F centers in NaCl, KCl, NaBr, and KBr. The migration of the F center through the bulk, across the (100) surface, and from the surface into the bulk was modeled. The activation enthalpy for the migration of an F center was calculated using dispersion-corrected generalized gradient approximation (GGA) functionals and a self-consistent dielectric-dependent global hybrid method based on plane-wave functions for the bulk and the (100) surface. The geometries of the transition states were characterized, and the position of the defect electron was determined. The influence of the theoretical methodology and the temperature dependence of the lattice parameter on the migration barrier was investigated. For the description of the bulk, thermal corrections were considered to enhance comparability with the experiment. The calculated migration enthalpies of 1.31, 1.46, and 1.32 eV for NaCl, KCl, and KBr, respectively, agree well with experimental measurements. For NaBr, a migration enthalpy of 0.93 eV is predicted. While only a direct hopping process between neighboring anion sites is found for the bulk, there are two possible pathways for some surfaces. The migration barrier on the surface and from the surface into the bulk is predicted to be lower than that in the bulk in all cases.

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Section: Introductionmentioning

confidence: 99%

Mobility of F Centers in Alkali Halides

Häfner

Bredow

2021

J. Phys. Chem. C

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“…35 The unoccupied * and * molecular orbitals of gas phase dioxygen yield features at photon energies of ϳ531 and ϳ540 eV in NEXAFS data. 43 This indicates that some -OH were adsorbed on the surface of the as-grown SiONWs forming the wSi-OH. The preedge feature was interpreted as O 1s → 2p tansitions toward the O 2p fraction in unoccupied states hybridized with the other element orbitals by some groups.…”

Section: Resultsmentioning

confidence: 98%

Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions

Lin

Tang

et al. 2007

Journal of Applied Physics

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Hole spectra and conductance for quantum wire systems under Rashba spin-orbit interaction J. Appl. Phys. 110, 113705 (2011) Structural and optical properties of m-plane GaN/AlGaN quantum wires grown by metalorganic chemical vapor deposition Appl. Phys. Lett. 99, 113106 (2011) Vibronic coupling in quantum wires: Applications to polydiacetylene Large-scale amorphous silicon oxide nanowires ͑SiONWs͒ have been synthesized from silicon monoxide powder under supercritically hydrothermal conditions. The chemical bonding of amorphous SiONWs were investigated with Fourier-transform infrared ͑FTIR͒ spectrometry and near-edge x-ray absorption fine structure ͑NEXAFS͒ spectrometry. Our results show that the SiONWs are tens of microns long with a diameter from tens to hundreds of nanometers. Selected area electron diffraction ͑SAED͒ shows that the samples are amorphous. Energy dispersive x-ray spectrometry ͑EDX͒ analysis reveals that the SiONWs consist of Si and O elements in an atomic ratio approximately equal to 1:1.5. The results of FTIR and NEXAFS indicate that some OH groups are located on the surface of the SiONWs in the form of wSi-OH. The relation between the chemical bonding and the possible growth mechanism was also discussed. During the growth process, water is an important species, which can provide H + and OH − under supercritically hydrothermal conditions. The H + and OH − block the defects of wSi-O• and wSi•, respectively, in the form of wSi-OH and stabilize the structure. The wSi-OH can reduce the adsorption activity of the SiONW surface which may be in favor of preventing the growth from the cross section and assisting the growth along the axial direction of the SiONWs.

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“…It is able to reduce different adsorbed molecules on the NaCl (100) surface 10,11 and split water. 12,13 Furthermore, several theoretical studies confirm the reductive power of the F center. 14−17 In this work, we extend our previous theoretical work and investigate the effect of the KCl and NaCl F center on a surface reaction.…”

Section: ■ Introductionmentioning

confidence: 88%

“…This can be achieved in various ways, for example, by adding gaseous alkaline metal, , heating the solid, irradiation, , or through electrolysis. , The reactivity of the F center has been demonstrated experimentally. It is able to reduce different adsorbed molecules on the NaCl (100) surface , and split water. , Furthermore, several theoretical studies confirm the reductive power of the F center. − …”

Section: Introductionmentioning

confidence: 93%

Nitrogen Activation on Defective Potassium Chloride and Sodium Chloride

Häfner

Bredow

2021

J. Phys. Chem. C

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The F center on the KCl and NaCl (100) surfaces was investigated theoretically concerning its effect on adsorbed nitrogen. It was found that the defect on both halide surfaces reduces an adsorbed nitrogen molecule and weakens its triple bond. A strong reduction of the rate-determining barriers was found for reaction of adsorbed nitrogen with hydrogen toward hydrazine compared to the gas phase. The frontier orbitals were analyzed, and the singly occupied π*-orbital of the reduced N 2 was identified as the driving force behind the enhanced reactivity. Surface cations further stabilize the transition structures by attractive interaction with dissociated H atoms. Gibbs free energy diagrams were calculated for all possible reaction pathways.

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Adsorption geometry of OH adsorbed atFcenters on a NaCl(100) surface

Cited by 31 publications

References 15 publications

Mobility of F Centers in Alkali Halides

Mobility of F Centers in Alkali Halides

Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions

Nitrogen Activation on Defective Potassium Chloride and Sodium Chloride

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