An X-Ray Photoelectron Spectroscopic Study of the Free Surface Segregation of Impurities in Platinum and Palladium

1987 ◽  
Vol 41 (3) ◽  
pp. 516-522
Author(s):  
Alan J. Paul ◽  
Peter M. A. Sherwood
Keyword(s):  
Free Surface ◽  
Spectroscopic Study ◽  
Photoelectron Spectroscopy ◽  
Surface Segregation ◽  
Pure Metal ◽  
Binding Energies ◽  
X Ray ◽  
The Core ◽  
Segregation Of Impurities ◽  
Elemental Form

X-ray photoelectron spectroscopy has been used to observe the free surface segregation of impurities in samples of platinum and palladium. Heating in vacuo to 600°C promoted the surface segregation of silver, gold, and carbon in platinum and the surface segregation of silver and sulfur in palladium. All species segregated in their elemental form. The core level binding energies of the silver and gold segregants were lower than those measured for the corresponding pure metal states.

scholarly journals Core-Level Photoemission From Stoichiometric GaN(0001)-1×1

2005 ◽  
Vol 10 ◽  
Author(s):  
S.M. Widstrand ◽  
K.O. Magnusson ◽  
L.S.O. Johansson ◽  
E. Moons ◽  
M. Gurnett ◽  
...  
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
Complex Structures ◽  
Dangling Bond ◽  
X Ray ◽  
The Core ◽  
Slight Excess ◽  
Bulk Gan

We report on a high-resolution x-ray photoelectron spectroscopy (HRXPS) study using synchrotron radiation, for the identification of the core level binding energies of Ga 3d and N 1s, from a stoichiometric Ga-polar GaN(0001)-1×1 sample.Three surface shifted components were found on the stoichiometric surface for the Ga 3d feature. The first surface shifted component has a higher binding energy of 0.85 eV, and is interpreted as surface Ga with one of the N bonds replaced by an empty dangling bond. This structure is belonging to the stoichiometric clean and ordered Ga-polar GaN(0001)-1×1 surface. The second, with a binding energy relative the bulk of −0.76 eV, is interpreted as Ga with one of the bonds to a Ga atom, which indicates a slight excess of Ga on the surface. The third surface shifted component is shifted by 2.01 eV and is related to gallium oxide in different configurations.The N 1s feature is complex with five surface shifted components relative the bulk were found. Two components with binding energy shifts of −0.54 eV and 0.47 eV are interpreted as surface shifted core levels from the stoichiometric, clean Ga-polar GaN(0001)-1×1 surface.We also analysed the Ga 3d spectrum after deposition of 1.5 ML of Ga on a stoichiometric surface. The surface shift for the Ga 3d5/2 component from the Ga overlayer is −1.74 eV relative the bulk GaN.The C 1s and O 1s core levels from remaining surface contamination have also been line shaped analysed and show complex structures.

ESCA and solid-state NMR studies of allophane

Clay Minerals ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 201-209 ◽  
Author(s):  
N. He ◽  
T. L. Barr ◽  
J. Klinowski
Keyword(s):  
Solid State ◽  
Surface Chemistry ◽  
Photoelectron Spectroscopy ◽  
Solid State Nmr ◽  
Bulk Material ◽  
Binding Energies ◽  
Nmr Studies ◽  
Near Surface ◽  
X Ray ◽  
The Core

AbstractThe surface/near-surface chemistry of allophane has been studied by X-ray photoelectron spectroscopy (ESCA) and the bulk material by 27A1 and 29Si solid-state NMR and other techniques. The surface/near-surface Si/Al ratio of allophane is c.1.0, similar to that for kaolinite, zeolite Na-A and sodalite. The core level binding energies for kaolinite and allophane are almost identical, but quite different from those for zeolite Na-A and sodalite, both framework aluminosilicates. The nature and size of these differences is consistent with the differences between the chemistry of sheet and framework silicates. The small variations in the Si(2p) spectra for kaolinite and allophane are discussed in terms of bonding of the tetrahedral units in the two materials.

A study of the core electron binding energies of ozone by x-ray photoelectron spectroscopy and the Xα scattered wave method

1977 ◽  
Vol 49 (2) ◽  
pp. 213-217 ◽  
Author(s):  
M.Salim Banna ◽  
David C. Frost ◽  
Charles A. McDowell ◽  
Louis Noodleman ◽  
Barry Wallbank
Keyword(s):  
Photoelectron Spectroscopy ◽  
Scattered Wave ◽  
Binding Energies ◽  
Wave Method ◽  
Core Electron ◽  
X Ray ◽  
The Core ◽  
Electron Binding Energies ◽  
Electron Binding

First-principles study of absolute XPS binding energy with PAW planewave pseudopotential method: application to tungsten disulfides

2021 ◽  
Author(s):  
Katsunori Tagami ◽  
Jun NARA ◽  
Takahisa Ohno ◽  
Mamoru Usami
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Theoretical Method ◽  
Metallic Phase ◽  
Binding Energies ◽  
Basis Set ◽  
Core Hole ◽  
X Ray ◽  
The Core ◽  
Projector Augmented Wave

Abstract We propose an efficient theoretical method to take into account the core-hole spin density in the projector augmented wave (PAW) method, combined with spin un-polarized pseudopotentials and the planewave basis set. We apply this method to the calculation of absolute core level X-ray photoelectron spectroscopy (XPS) binding energies of WS2 and its related materials, and find the following points. First, inclusion of core-hole spin in the core-exited state is essential for accurate description of the binding energies, especially for light elements. Second, the calculated absolute binding energies show excellent agreement with experimental results. Finally, when oxygen atoms are incorporated in the basal plane of WS2 in the metallic phase, the O 1s binding energy is expected to appear at lower energy than the corresponding value in the semiconducting phase.

X-ray photoelectron spectroscopy of Cu–In–Se–N and Cu–In–Se thin films

1992 ◽  
Vol 7 (8) ◽  
pp. 1984-1986 ◽  
Author(s):  
Shigemi Kohiki ◽  
Mikihiko Nishitani ◽  
Takayuki Negami ◽  
Takahiro Wada
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Electron ◽  
X Ray ◽  
The Core ◽  
Bonding Interaction ◽  
Electron Binding Energies ◽  
Electron Binding

The Cu, In, and Se core-level electron binding energies of the p-type Cu–In–Se–N thin film were larger than those of the n-type Cu–In–Se thin film. The positive shift of the core-electron binding energies for the Cu–In–Se–N film is consistent with that expected from the conduction types of the films. Holes were positioned in the Cu–Se antibonding orbitals of the Cu–In–Se–N film. The analysis using the Auger parameter revealed that the Cu–Se bonding interaction is stronger for the Cu–In–Se–N film than for the Cu–In–Se film.

Characterizing the Thermomechanical Degradation of a Filled Elastomer by Morphology and X Ray Photoelectron Spectroscopy

2001 ◽  
Vol 702 ◽  
Author(s):  
Giovanni F Crosta ◽  
Art J Nelson ◽  
Marina C Camatini
Keyword(s):  
Photoelectron Spectroscopy ◽  
Intrinsic Property ◽  
Binding Energies ◽  
Structural Domain ◽  
X Ray ◽  
Vulcanized Rubber ◽  
A Value ◽  
Debris Particles ◽  
Morphological Descriptor ◽  
Microscopy Images

ABSTRACTThree types of debris particles, denoted by L2, H2 and K3 respectively, originated from the abrasion of silica-filled, vulcanized rubber under different test conditions (severity) were analyzed and compared. The structural fractal dimension, DFS, of the particle perimeter was chosen as a morphological descriptor (but not necessarily as an intrinsic property of the fractured material !). Said dimension was estimated by processing light microscopy images. A value of the morphological threshold, TST, which separates the textural from the structural domain in the RICHARDSON plot was determined in order to maximize discrimination between the three particle types and rank them by increasing values of DFS. Particles from the highest severity test (K3) exhibited the highest value of DFS. X ray photoelectron spectroscopy (XPS) provided elemental composition, core level binding energies and the speciation of C, N, O, Si and S. As a result, L2 debris was found to originate from two processes: fracture of rubber and segregation of extender oil. Evidence has come both from morphology and XPS. Particles of H2 and K3 were ascribed to fracture alone. Comparison between K3 and the reference material, rasped rubber (RAS), shows the following: a) increase of the [S]/[C] surface atomic concentration ratio from RAS to K3; b) existence of multiple bonding states of S in K3 with energy peaking at 162.9 ± 0.3 eV ([-S-S-]n); c) weak contribution of R-S-O-R oxidized S species in K3 at 165 eV, not seen in RAS; d) no evidence of either SO3 or SO4 groups in any material. Although preliminary, these results prove the ability of morphological analysis and XPS to characterize the surface properties of debris particles non destructively.

Electronic structure modification in Fe substituted β-Ga2O3 from resonant photoemission and soft x-ray absotption spectroscopies

2021 ◽  
Author(s):  
Sahadeb Ghosh ◽  
Mangala Nand ◽  
Rajiv Kamparath ◽  
Mukul Gupta ◽  
Devdatta M Phase ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Rf Magnetron Sputtering ◽  
Binding Energies ◽  
Transfer System ◽  
Structure Modification ◽  
X Ray ◽  
Resonant Photoemission ◽  
A Charge ◽  
Fe Substitution

Abstract Oriented thin films of β-(Ga1-xFex)2O3 have been deposited by RF magnetron sputtering on c-Al2O3 and GaN substrates. The itinerant character of Fe 3d states forming the top of the valence band (VB) of Fe substituted of β-Ga2O3 thin films has been determined from resonant photoelectron spectroscopy (RPES). Further, admixture of itinerant and localized character of these Fe 3d sates is obtained for larger binding energies i.e deeper of VB. The bottom of the conduction band (CB) for β-(Ga1-xFex)2O3 is also found to be strongly hybridized states involving Fe 3d and O 2p states as compared to that of Ga 4s in pristine β-Ga2O3. This suggests that β-Ga2O3 transforms from band like system to a charge transfer system with Fe substitution. Furthermore, the bandgap red shits with Fe composition, which has been found to be primarily related to the shift of the CB edge.

scholarly journals Synthesis of new Ln4(Al2O6F2)O2 (Ln = Sm, Eu, Gd) phases with a cuspidine-related structure

IUCrJ ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Aroa Morán-Ruiz ◽  
Aritza Wain-Martin ◽  
Alodia Orera ◽  
María Luisa Sanjuán ◽  
Aitor Larrañaga ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Raman Spectra ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Temperature Reaction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Vinylidene Difluoride ◽  
Vacant Position

The first fluorination of the cuspidine-related phases of Ln4(Al2O7□)O2 (where Ln = Sm, Eu, Gd) is reported. A low-temperature reaction with poly(vinylidene difluoride) lead to the fluorine being substituted in place of oxygen and inserted into the vacant position between the dialuminate groups. X-ray photoelectron spectroscopy shows the presence of the F 1s photoelectron together with an increase in Al 2p and rare-earth 4d binding energies supporting F incorporation. Energy-dispersive X-ray spectroscopy analyses are consistent with the formula Ln4(Al2O6F2)O2, confirming that substitution of one oxygen by two fluoride atoms has been achieved. Rietveld refinements show an expansion in the cell upon fluorination and confirm that the incorporation of fluoride in the Ln4(Al2O7□)O2 structure results in changes in Al coordination from four to five. Thus, the isolated tetrahedral dialuminate Al2O7 groups are converted to chains of distorted square-based pyramids. These structural results are also discussed based on Raman spectra.

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