Deduction of the chemical state and the electronic structure of Nd2Fe14B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra

2014 ◽  
Vol 116 (16) ◽  
pp. 163917 ◽  
Author(s):  
Jing Wang ◽  
Le Liang ◽  
Lanting Zhang ◽  
Limin Sun ◽  
Shinichi Hirano
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
Chemical State ◽  
X Ray ◽  
Band Spectra

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.

X-Ray Photoelectron Spectroscopic Studies of Carbon Fiber Surfaces. Part XVI: Core-Level and Valence-Band Studies of Pitch-Based Fibers Electrochemically Treated in Ammonium Carbonate Solution

1992 ◽  
Vol 46 (4) ◽  
pp. 645-651 ◽  
Author(s):  
Yaoming Xie ◽  
Tiejun Wang ◽  
Oliver Franklin ◽  
Peter M. A. Sherwood
Keyword(s):  
Carbon Fiber ◽  
Valence Band ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Spectroscopic Studies ◽  
Core Level ◽  
Short Treatment ◽  
X Ray ◽  
Band Spectra

DuPont E-120 high-modulus pitch-based carbon fibers were treated electrochemically in 0.5 M (NH4)2CO3 solution under both potentiostatic and galvanostatic modes. X-ray photoelectron spectroscopy (XPS) was used to monitor the chemical changes on the carbon fiber surfaces. Both core-level and valence-band spectra showed that the treatment introduced both oxygen-containing and nitrogen-containing functional groups onto the fiber surfaces, and the mainly oxygen-containing functional groups produced were carbonyl (C=O) type functional groups after longer treatment time. For short treatment time, hydroxide (C-OH) type groups were the dominant functionality, and ether (C-O-C) or epoxide type groups were also formed. The O 2 s peaks from oxygen atoms in the hydroxide functionality and the ether or epoxide groups are well separated in the valence-band spectra; the corresponding O 1 s peaks, however, are not separated in the O 1 s core-region spectra.

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.

X-Ray Photoelectron Spectroscopy Studies of Photochemical Changes in High-Performance Fibers

1993 ◽  
Vol 47 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Lois E. Hamilton ◽  
Peter M. A. Sherwood ◽  
Barbara M. Reagan
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Light Exposure ◽  
High Thermal Stability ◽  
Core Level ◽  
Aramid Fibers ◽  
X Ray ◽  
Photo Oxidation ◽  
Band Spectra ◽  
Spectroscopy Studies

The double bonds and aromaticity that impart high thermal stability in fibers often increase the absorption of LTV radiation, resulting in greater susceptibility to photodegradation. This study compares the resistance of three high-performance fibers (Nomex aramid, Kynol novoloid, and PBI) to accelerated light exposure. X-ray photoelectron spectroscopy (XPS) was used to evaluate the photochemical changes on the surfaces of the fibers. On the basis of the C 1 s core-level spectra and oxygen/carbon atomic ratios, the Nomex aramid fibers were photo-oxidized more rapidly than Kynol novoloid and PBI fibers. Similarly, Nomex aramid fibers exhibited more rapid strength losses than the other fibers. We propose that tautomerization inhibited photodegradation in the Kynol novoloid and PBI fibers. XPS core-level and valence-band spectra interpreted by ab initio calculations are shown to be valuable probes of photo-oxidation in fibers.

Electronic Structure of h-WO3 and CuWO4 Nanocrystals, Harvesting Materials for Renewable Energy Systems and Functional Devices

2011 ◽  
Vol 110-116 ◽  
pp. 2188-2193 ◽  
Author(s):  
V.V. Atuchin ◽  
I.B. Troitskaia ◽  
O.Yu. Khyzhun ◽  
V.L. Bekenev ◽  
Yu.M. Solonin
Keyword(s):  
Electronic Structure ◽  
Renewable Energy ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Emission Spectroscopy ◽  
Energy Production ◽  
Energy Systems ◽  
Renewable Energy Systems ◽  
X Ray ◽  
Valence Band Region

— The electronic structure of hexagonal WO3 and triclinic CuWO4 nanocrystals, prospective materials for renewable energy production and functional devices, has been studied using the X-ray photoelectron spectroscopy (XPS) and X-ray emission spectroscopy (XES) methods. The present XPS and XES results render that the W 5d-and O 2p-like states contribute throughout the whole valence-band region of the h-WO3 and CuWO4 nanocrystalline materialls, however maximum contributions of the O 2p-like states occur in the upper, whilst the W 5d-like states in the lower portions of the valence band, respectively.

The Surface Analysis of Nickel Chromia Catalysts by X-Ray Photoelectron Spectroscopy

1973 ◽  
Vol 51 (10) ◽  
pp. 1670-1672 ◽  
Author(s):  
Norman Stewart McIntyre ◽  
Norman Henry Sagert ◽  
Rita Mary Louise Pouteau ◽  
Warren George Proctor
Keyword(s):  
Valence Band ◽  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Isotope Exchange ◽  
Surface Composition ◽  
X Ray ◽  
Hydrogen Water ◽  
Band Spectra ◽  
Composition Changes

The surface composition of a series of nickel–chromia catalysts has been examined by X-ray photoelectron spectroscopy. Correlation of the amount of available surface nickel with the activity of the particular catalyst for hydrogen water deuterium isotope exchange is very good. No significant alterations are observed in the valence band spectra as the surface composition changes.

Valence band electronic structure of carbon nitride from x-ray photoelectron spectroscopy

2002 ◽  
Vol 92 (1) ◽  
pp. 281-287 ◽  
Author(s):  
Z. Y. Chen ◽  
J. P. Zhao ◽  
T. Yano ◽  
T. Ooie
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
X Ray
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