scholarly journals Electronic Structure Theory for X-Ray Absorption and Photoemission Spectroscopy

2021 ◽  
pp. 63-81
Author(s):  
Peter Krüger
Keyword(s):  
Electronic Structure ◽  
Electron Correlation ◽  
Density Functional ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Photoemission Spectroscopy ◽  
Functional Theory ◽  
X Ray ◽  
Hartree Fock ◽  
X Ray Absorption

AbstractThe principles of X-ray absorption and photoemission spectroscopy calculations are introduced and the basics of electronic structure theory, including the Hartree–Fock approximation, density functional theory, its time-dependent version and quasiparticle theory are reviewed on an elementary level. Emphasis is put on polarization effects and the role played by electron correlation.

scholarly journals Orientation and stability of a bi-functional aromatic organic molecular adsorbate on silicon

2016 ◽  
Vol 18 (39) ◽  
pp. 27290-27299 ◽  
Author(s):  
K. M. O'Donnell ◽  
H. Hedgeland ◽  
G. Moore ◽  
A. Suleman ◽  
M. Siegl ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Room Temperature ◽  
Photoemission Spectroscopy ◽  
Scanning Tunneling ◽  
Adsorption Behaviour ◽  
Tunneling Microscopy ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Absorption

In this work we combine scanning tunneling microscopy, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission spectroscopy and density functional theory to resolve a long-standing confusion regarding the adsorption behaviour of benzonitrile on Si(001) at room temperature.

Electronic structure of twisted and planar rubrene molecules: a density functional study

2018 ◽  
Vol 20 (27) ◽  
pp. 18623-18629 ◽  
Author(s):  
T. Mukherjee ◽  
Sumona Sinha ◽  
M. Mukherjee
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Of States ◽  
Electron Density Distribution ◽  
Density Functional ◽  
Functional Study ◽  
Functional Theory ◽  
X Ray ◽  
Homo And Lumo ◽  
X Ray Absorption

X-ray absorption spectra (XAS), the density of states (DOS) and the electron density distribution of the HOMO and LUMO for flat and twisted rubrene molecules have been calculated using density functional theory (DFT).

scholarly journals Quantum-electrodynamical density-functional theory: Bridging quantum optics and electronic-structure theory

2014 ◽  
Vol 90 (1) ◽  
Author(s):  
Michael Ruggenthaler ◽  
Johannes Flick ◽  
Camilla Pellegrini ◽  
Heiko Appel ◽  
Ilya V. Tokatly ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Quantum Optics ◽  
Density Functional ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Functional Theory

Solid energy calibration standards for PK-edge XANES: electronic structure analysis of PPh4Br

2018 ◽  
Vol 25 (2) ◽  
pp. 529-536 ◽  
Author(s):  
Anastasia V. Blake ◽  
Haochuan Wei ◽  
Courtney M. Donahue ◽  
Kyounghoon Lee ◽  
Jason M. Keith ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Energy Calibration ◽  
Functional Theory ◽  
Calibration Standards ◽  
X Ray ◽  
X Ray Absorption ◽  
Edge Feature

PK-edge X-ray absorption near-edge structure (XANES) spectroscopy is a powerful method for analyzing the electronic structure of organic and inorganic phosphorus compounds. Like all XANES experiments, PK-edge XANES requires well defined and readily accessible calibration standards for energy referencing so that spectra collected at different beamlines or under different conditions can be compared. This is especially true for ligandK-edge X-ray absorption spectroscopy, which has well established energy calibration standards for Cl (Cs2CuCl4) and S (Na2S2O3·5H2O), but not neighboring P. This paper presents a review of common PK-edge XANES energy calibration standards and analysis of PPh4Br as a potential alternative. The PK-edge XANES region of commercially available PPh4Br revealed a single, highly resolved pre-edge feature with a maximum at 2146.96 eV. PPh4Br also showed no evidence of photodecomposition when repeatedly scanned over the course of several days. In contrast, we found that PPh3rapidly decomposes under identical conditions. Density functional theory calculations performed on PPh3and PPh4+revealed large differences in the molecular orbital energies that were ascribed to differences in the phosphorus oxidation state (IIIversusV) and molecular charge (neutralversus+1). Time-dependent density functional theory calculations corroborated the experimental data and allowed the spectral features to be assigned. The first pre-edge feature in the PK-edge XANES spectrum of PPh4Br was assigned to P 1s → P-C π* transitions, whereas those at higher energy were P 1s → P-C σ*. Overall, the analysis suggests that PPh4Br is an excellent alternative to other solid energy calibration standards commonly used in PK-edge XANES experiments.

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