XPS Spectra and Optical Reflectivity of Yttrium Stabilised Zirconia

1992 ◽  
Vol 293 ◽  
Author(s):  
P. Camagni ◽  
L.E. Depero ◽  
F. Parmigiani ◽  
G. Samoggia ◽  
L. Sangaletri ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Synchrotron Radiation ◽  
Energy Range ◽  
Single Crystals ◽  
Valence Band ◽  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Electron Excitation ◽  
Xps Spectra ◽  
X Ray

AbstractX-ray photoelectron spectroscopy measurements and synchrotron radiation reflectivity and measurements in the photon energy range between 5eV and 30 eV are reported for yttrium stabilised zirconia single crystals. From the present data some behaviour of the valence band and conduction band electronic structure are elucidated. Two features present in the valence band XPS spectra, not explained on the basis of one-clectron theory, are tentatively assigned to simultaneous two electron excitation.

scholarly journals Electronic structure and chemical bond nature in Cs2NpO2Cl4

2017 ◽  
Vol 32 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Yury Teterin ◽  
Konstantin Maslakov ◽  
Mikhail Ryzhkov ◽  
Anton Teterin ◽  
Kirill Ivanov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Binding Energy ◽  
Energy Range ◽  
Valence Band ◽  
Chemical Bond ◽  
Photoelectron Spectroscopy ◽  
Theoretical Calculations ◽  
Molecular Orbitals ◽  
X Ray ◽  
Outer Valence

On the basis of the X-ray photoelectron spectroscopy data and results of theoretical calculations for the NpO2Cl4 (D4h) cluster, the electronic structure and the chemical bond nature in , was done in the binding Cs2NpO2Cl4 single crystal, containing the neptunyl group NpO2 energy range of 0 eV to ~35 eV. The filled Np 5f electronic states were established to form in the valence band of Cs2NpO2Cl4. This was attributed to the direct participation of the Np 5f electrons in the chemical bonding. The Np 6p electrons were shown to participate in formation of both the inner valence band (~15 eV-~35 eV) and the outer valence band (0 eV-~15 eV). The filled Np 6p and the O 2s, Cl 3s electronic shells were found to make the largest contribution to the formation of the inner valence molecular orbitals. The molecular orbitals composition and the sequence order in the binding energy range 0 eV-~35 eV in Cs2NpO2Cl4, were established. For the first time the quantitative scheme of molecular orbitals for the NpO2Cl4 cluster in the binding energy range 0 eV-~35 eV, was built. This scheme reflects neptunium close environment in the studied compound and is fundamental for both understanding the chemical bond nature in Cs2NpO2Cl4 and the interpretation of other X-ray spectra of Cs2NpO2Cl4. The contributions to the chemical binding for the NpO2Cl4 cluster were evaluated to be: the outer valence molecular orbitals contribution - 73 %, and the inner valence molecular orbitals contribution - 27 %.

X-ray photoelectron spectroscopy characterization of barium titanate ceramics prepared by the citric route. Residual carbon study

1997 ◽  
Vol 12 (9) ◽  
pp. 2388-2392 ◽  
Author(s):  
C. Miot ◽  
E. Husson ◽  
C. Proust ◽  
R. Erre ◽  
J. P. Coutures
Keyword(s):  
Barium Titanate ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Residual Carbon ◽  
Ion Etching ◽  
Xps Spectra ◽  
X Ray ◽  
Titanate Ceramics

Powder and ceramics of barium titanate prepared by the citric process were studied by x-ray photoelectron spectroscopy (XPS). Spectra of C1s, O1s, Ti2p, Ba3d, and Ba4d levels are analyzed in powder and ceramics immediately after the sintering step and after several months of exposure in the air. Ar-ion etching allowed one to characterize the material intrinsic carbon. The results are discussed in comparison with works previously published on oxide single crystals.

Bulk and Surface Electronic Structure of GaN Measured Using Angle-Resolved Photoemission, Soft X-ray Emission and Soft X-ray Absorption

1996 ◽  
Vol 449 ◽  
Author(s):  
Kevin E. Smith ◽  
Sarnjeet S Dhesi ◽  
Laurent-C. Duda ◽  
Cristian B Stagarescu ◽  
J. H. Guo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Brillouin Zone ◽  
Emission Spectra ◽  
Partial Density ◽  
High Symmetry ◽  
X Ray ◽  
X Ray Absorption

ABSTRACTThe electronic structure of thin film wurtzite GaN has been studied using a combination of angle resolved photoemission, soft x-ray absorption and soft x-ray emission spectroscopies. We have measured the bulk valence and conduction band partial density of states by recording Ga L- and N K- x-ray emission and absorption spectra. We compare the x-ray spectra to a recent ab initio calculation and find good overall agreement. The x-ray emission spectra reveal that the top of the valence band is dominated by N 2p states, while the x-ray absorption spectra show the bottom of the conduction band as a mixture of Ga 4s and N 2p states, again in good agreement with theory. However, due to strong dipole selection rules we can also identify weak hybridization between Ga 4s- and N 2p-states in the valence band. Furthermore, a component to the N K-emission appears at approximately 19.5 eV below the valence band maximum and can be identified as due to hybridization between N 2p and Ga 3d states. We report preliminary results of a study of the full dispersion of the bulk valence band states along high symmetry directions of the bulk Brillouin zone as measured using angle resolved photoemission. Finally, we tentatively identify a non-dispersive state at the top of the valence band in parts of the Brillouin zone as a surface state.

BBonding in minerals: the application of PAX (photoelectron and X-ray) spectroscopy to the direct determination of electronic structure

1989 ◽  
Vol 53 (370) ◽  
pp. 153-164 ◽  
Author(s):  
David S. Urch
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Direct Determination ◽  
Energy Scale ◽  
X Ray ◽  
Electron Transitions ◽  
Dipole Selection Rule ◽  
The Individual

AbstractX-ray photoelectron spectroscopy can be used to measure the ionization energies of electrons in both valence band and core orbitals. As core vacancies are the initial states for X-ray emission, a knowledge of their energies for all atoms in a mineral enables all the X-ray spectra to be placed on a common energy scale. X-ray spectra are atom specific and are governed by the dipole selection rule. Thus the individual bonding roles of the different atoms are revealed by the fine structure of valence X-ray peaks (i.e. peaks which result from electron transitions between valence band orbitals and core vacancies). The juxtaposition of such spectra enables the composition of the molecular orbitals that make up the chemical bonds of a mineral to be determined.Examples of this approach to the direct determination of electronic structure are given for silica, forsterite, brucite, and pyrite. Multi-electron effects and developments involving anisotropic X-ray emission from single crystals are also discussed.

Characterization of europium implanted LiNbO3

1993 ◽  
Vol 8 (10) ◽  
pp. 2679-2685 ◽  
Author(s):  
P. Moretti ◽  
B. Canut ◽  
S.M.M. Ramos ◽  
R. Brenier ◽  
P. Thévenard ◽  
...  
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Rutherford Backscattering ◽  
Oxidation States ◽  
Xps Spectra ◽  
X Ray ◽  
Partial Recrystallization ◽  
Lower Charge

LiNbO3 single crystals were implanted at room temperature with Eu+ ions at 70 keV with fluence ranging from 0.5 to 5 × 1016 ions · cm−2. The damage in the implanted layer has been investigated by Channeling Rutherford Backscattering (RBS-C), and the oxidation states of the cations have been determined by x-ray photoelectron spectroscopy (XPS). Following implantation, a fully amorphized layer of 60 nm is generated, even for the lowest fluence employed. Subsequent annealing in air, in the range 800–1250 K, was applied to restore tentatively the crystallinity and promote the substitutional incorporation of Eu in the crystal. Only a partial recrystallization of the damaged layer was observed. For as-implanted samples, XPS spectra clearly reveal europium in Eu2+ and Eu3+ states, and the Nb5+ ions are driven to lower charge states.

scholarly journals Влияние адсорбции атомов натрия и прогрева на наночастицы золота, адсорбированные на вольфраме

2020 ◽  
Vol 62 (8) ◽  
pp. 1171
Author(s):  
П.А. Дементьев ◽  
Е.В. Иванова ◽  
М.Н. Лапушкин ◽  
Д.А. Cмирнов ◽  
С.Н. Тимошнев
Keyword(s):  
Gold Nanoparticles ◽  
Electronic Structure ◽  
Energy Range ◽  
Surface Topography ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Sodium Atoms ◽  
Before And After ◽  
Tungsten Surface

The electronic structure of gold nanoparticles deposited on the surface of tungsten before and after the adsorption of sodium atoms followed by heating at T = 630 K was studied in situ in ultrahigh vacuum by photoelectron spectroscopy. The photoemission spectra from the valence band and core levels of Au 4f and Na 2p were studied under synchrotron excitation in the photon energy range 80-600 eV. It was shown that changes in the spectra of the valence band and core levels of Au 4f and Na 2p are associated with a change in the surface topography caused by the adsorption of sodium atoms and heating, which led to an increase in the surface area by several times. The surface topography and cathodoluminescence of a layer of gold nanoparticles deposited on a tungsten surface are studied

The study of the electronic structure of some N-heterocyclic carbenes (NHCs) by variable energy photoelectron spectroscopy

2015 ◽  
Vol 17 (16) ◽  
pp. 10656-10667 ◽  
Author(s):  
Branka Kovač ◽  
Ivan Ljubić ◽  
Antti Kivimäki ◽  
Marcello Coreno ◽  
Igor Novak
Keyword(s):  
Electronic Structure ◽  
Synchrotron Radiation ◽  
Computational Methods ◽  
Photoelectron Spectroscopy ◽  
Electronic Structures ◽  
Heterocyclic Carbenes ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Variable Energy

UV and X-ray photoelectron spectra of three N-heterocyclic carbenes under synchrotron radiation reveal details of their electronic structure and are used as a benchmark to test computational methods for treating core ionizations in systems with unusual electronic structures.

scholarly journals Photocatalytical Properties and Theoretical Analysis of N, Cd-Codoped TiO2Synthesized by Thermal Decomposition Method

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Hongtao Gao ◽  
Bing Lu ◽  
Fangfang Liu ◽  
Yuanyuan Liu ◽  
Xian Zhao
Keyword(s):  
Thermal Decomposition ◽  
Theoretical Analysis ◽  
Valence Band ◽  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Decomposition Method ◽  
Density Functional ◽  
X Ray ◽  
Thermal Decomposition Method ◽  
Bet Specific Surface Area

N, Cd-codoped TiO2have been synthesized by thermal decomposition method. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-visible diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) specific surface area analysis, respectively. The products represented good performance in photocatalytic degradation of methyl orange. The effect of the incorporation of N and Cd on electronic structure and optical properties of TiO2was studied by first-principle calculations on the basis of density functional theory (DFT). The impurity states, introduced by N 2p or Cd 5d, lied between the valence band and the conduction band. Due to dopants, the band gap of N, Cd-codoped TiO2became narrow. The electronic transition from the valence band to conduction band became easy, which could account for the observed photocatalytic performance of N, Cd-codoped TiO2. The theoretical analysis might provide a probable reference for the experimentally element-doped TiO2synthesis.

Effects of Potassium Chemisorption on the Electronic Structure of VxOy/TiO2 Surfaces

1996 ◽  
Vol 454 ◽  
Author(s):  
Fulvio Parmigiani ◽  
Laura E. Depero ◽  
Luigi Sangaletti
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Open Shell ◽  
Band Edge ◽  
X Ray ◽  
Core Line ◽  
Band Spectra ◽  
Gap States ◽  
Vanadium Ions

ABSTRACTX-ray photoelectron spectroscopy of pure and K chemisorbed VxOy/TiO2 powders are reported. Core-line and valence band spectra suggest the presence of vanadium open shell ions on the pure VxOy/TiO2 interface, whereas potassium vanadate seems to form after K chemisorption. That results in the presence of a significant amount of gap states, with vanadium character, just above the O2p band edge, for the pure VxOy/TiO2 powder, while K chemisorption, reducing significantly the open shell vanadium ions, quenches the gap emission in the XPS valence band spectra.

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