scholarly journals Determination of the valence band edge of Fe oxide nanoparticles dispersed in aqueous solution through resonant photoelectron spectroscopy from a liquid microjet

2021 ◽  
Author(s):  
Giorgia Olivieri ◽  
Gregor Kladnik ◽  
Dean Cvetko ◽  
Matthew A. Brown
Keyword(s):  
Aqueous Solution ◽  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Band Edge ◽  
Photoemission Spectroscopy ◽  
Oxide Nanoparticles ◽  
Valence Band Edge ◽  
Resonant Photoemission

The electronic structure of hydrated nanoparticles can be unveiled by coupling a liquid microjet with a resonant photoemission spectroscopy.

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.

Electronic Structure of Defects in Amorphous Silicon Nitride

1992 ◽  
Vol 284 ◽  
Author(s):  
John Robertson
Keyword(s):  
Electronic Structure ◽  
Silicon Nitride ◽  
Percolation Threshold ◽  
Amorphous Silicon ◽  
Electronic Properties ◽  
Valence Band ◽  
Band Edge ◽  
Valence Band Edge ◽  
Dangling Bonds ◽  
Amorphous Silicon Nitride

ABSTRACTThe paper reviews the electronic properties of defects in amorphous silicon nitride (a-Si3N4) and the hydrogenated alloys a-SiNx:H. The main defects in a-Si3N4 are the Si and N dangling bonds (DBs). The Si DB forms a sp3 state near midgap, while the N DB forms a highly localized pπ level just above the valence band edge. The behaviour of the alloys changes near x ≈ 1.1, the percolation threshold of Si-Si bonds. In the Si-rich alloys, both band edges are Si-like, only Si DBs are seen and their density is controlled by equilibration with weak Si-Si bonds. The x>1.1 alloys behave like silicon nitride; the valence band changes towards N pπ-like, both Si and N DBs can arise, the Si DB can have a high density and prefers to be in its charged diamagnetic configurations.

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.

scholarly journals Accurate determination of the valence band edge in hard x-ray photoemission spectra using GW theory

2016 ◽  
Vol 119 (16) ◽  
pp. 165703 ◽  
Author(s):  
Johannes Lischner ◽  
Slavomír Nemšák ◽  
Giuseppina Conti ◽  
Andrei Gloskovskii ◽  
Gunnar Karl Pálsson ◽  
...  
Keyword(s):  
Valence Band ◽  
Accurate Determination ◽  
Band Edge ◽  
Valence Band Edge ◽  
X Ray

Surface electronic structure of CeCo2, CeRh2 and CeRh3 probed by valence band resonant photoemission spectroscopy

1995 ◽  
Vol 331-333 ◽  
pp. 1229-1232 ◽  
Author(s):  
G. Chiaia ◽  
P. Vavassori ◽  
L. Duò ◽  
L. Braicovich ◽  
M. Qvarford ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoemission Spectroscopy ◽  
Resonant Photoemission ◽  
Surface Electronic Structure

scholarly journals Attosecond intra-valence band dynamics and resonant-photoemission delays in W(110)

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
S. Heinrich ◽  
T. Saule ◽  
M. Högner ◽  
Y. Cui ◽  
V. S. Yakovlev ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Electronic Band Structure ◽  
Photoelectric Effect ◽  
Final State ◽  
Electronic Band ◽  
Time Resolved ◽  
Resonant Photoemission ◽  
Pulse Trains ◽  
Electron Correlation Effects

AbstractTime-resolved photoelectron spectroscopy with attosecond precision provides new insights into the photoelectric effect and gives information about the timing of photoemission from different electronic states within the electronic band structure of solids. Electron transport, scattering phenomena and electron-electron correlation effects can be observed on attosecond time scales by timing photoemission from valence band states against that from core states. However, accessing intraband effects was so far particularly challenging due to the simultaneous requirements on energy, momentum and time resolution. Here we report on an experiment utilizing intracavity generated attosecond pulse trains to meet these demands at high flux and high photon energies to measure intraband delays between sp- and d-band states in the valence band photoemission from tungsten and investigate final-state effects in resonant photoemission.

scholarly journals Calculation of Band Offsets of Mg(OH)2-Based Heterostructures

2021 ◽  
Vol 2 (3) ◽  
pp. 274-283
Author(s):  
Masaya Ichimura
Keyword(s):  
Solar Cells ◽  
Valence Band ◽  
Dye Sensitized Solar Cells ◽  
Band Alignment ◽  
First Principles Calculation ◽  
Band Edge ◽  
Level Energy ◽  
Type I ◽  
Valence Band Edge ◽  
Generalized Gradient

The band alignment of Mg(OH)2-based heterostructures is investigated based on first-principles calculation. (111)-MgO/(0001)-Mg(OH)2 and (0001)-wurtzite ZnO/(0001)-Mg(OH)2 heterostructures are considered. The O 2s level energy is obtained for each O atom in the heterostructure supercell, and the band edge energies are evaluated following the procedure of the core-level spectroscopy. The calculation is based on the generalized gradient approximation with the on-site Coulomb interaction parameter U considered for Zn. For MgO/Mg(OH)2, the band alignment is of type II, and the valence band edge of MgO is higher by 1.6 eV than that of Mg(OH)2. For ZnO/Mg(OH)2, the band alignment is of type I, and the valence band edge of ZnO is higher by 0.5 eV than that of Mg(OH)2. Assuming the transitivity rule, it is expected that Mg(OH)2 can be used for certain types of heterostructure solar cells and dye-sensitized solar cells to improve the performance.

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