High Spin Mn Molecular Clusters: Spin State Effects On the Outer Core-Level Multiplet Structures

2001 ◽  
Vol 635 ◽  
Author(s):  
A. J. Nelson ◽  
J. G. Reynolds ◽  
George Christou
Keyword(s):  
Single Molecule ◽  
Electron Correlation ◽  
Cluster Size ◽  
Branching Ratio ◽  
Outer Core ◽  
Photoemission Spectroscopy ◽  
Final State ◽  
X Ray ◽  
Mn Cluster ◽  
S States

AbstractOxo-bridged manganese polynuclear complexes have applications in a variety of technologies, such as single-molecule nanomagnets, catalysis and photosynthetic redox chemistry. The reason that these types of compounds are capable of such important and varied technologies is thought to be because they possess ground states with large spin values. However, the electronic, structural and magnetochemical relationships are not well understood and need to be thoroughly investigated to adequately explain why Mn is such an integral part of so many useful processes. X-ray photoemission spectroscopy was used to study the Mn 3p, 3s and valence band electronic behavior as a function of Mn cluster structural properties, where the cluster size and nuclearity are systematically varied. Results show a chemical shift of the Mn 3p3/2,1/2 spin-orbit pair related to the cluster size and nuclearity. Also, the Mn 3s 7S and 5S final state multiplet components shift since they involve the binding energy of a ligand valence electron. In addition, the branching ratio of the 7S:5S states is related to the 3s–3d electron correlation. Specifically, in the 7S state, the remaining 3s electron is well correlated with 3d electrons of parallel spin, while in the 5S state the two spins are antiparallel. Changes in this electron correlation are clearly observed in the 7S:5S branching ratio as a function of cluster size and ligand electronegativity.

scholarly journals Structure of the manganese complex in photosystem II: insights from X–ray spectroscopy

2002 ◽  
Vol 357 (1426) ◽  
pp. 1347-1358 ◽  
Author(s):  
Vittal K. Yachandra
Keyword(s):  
Fine Structure ◽  
Emission Spectroscopy ◽  
Structural Models ◽  
Oxidation States ◽  
X Ray ◽  
X Ray Scattering ◽  
Raman Process ◽  
Mn Cluster ◽  
X Ray Absorption ◽  
S States

We have used Mn K–edge absorption and Kβ emission spectroscopy to determine the oxidation states of the Mn complex in the various S states. We have started exploring the new technique of resonant inelastic X–ray scattering spectroscopy; this technique can be characterized as a Raman process that uses K–edge energies (1s to 4p, ca . 6550 eV) to obtain L–edge–like spectra (2p to 3d, ca . 650 eV). The relevance of these data to the oxidation states and structure of the Mn complex is presented. We have obtained extended X–ray absorption fine structure data from the S 0 and S 3 states and observed heterogeneity in the Mn–Mn distances leading us to conclude that there may be three rather than two di– μ –oxo–bridged units present per tetranuclear Mn cluster. In addition, we have obtained data using Ca and Sr X–ray spectroscopy that provide evidence for a heteronuclear Mn1Ca cluster. The possibility of three di– μ –oxo–bridged Mn–Mn moieties and the proximity of Ca is incorporated into developing structural models for the Mn cluster. The involvement of bridging and terminal O ligands of Mn in the mechanism of oxygen evolution is discussed in the context of our X–ray spectroscopy results.

scholarly journals Effect of electron correlation in the decomposition of core level binding energy shifts into initial and final state contributions

2019 ◽  
Vol 21 (18) ◽  
pp. 9399-9406 ◽  
Author(s):  
Marc Figueras ◽  
Carmen Sousa ◽  
Francesc Illas
Keyword(s):  
Binding Energy ◽  
Electron Correlation ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
Final State ◽  
X Ray ◽  
Core Level Binding Energy

The influence of electron correlation into the decomposition of core level binding energy shifts, measured by X-ray photoelectron spectroscopy (XPS), into initial and final effects is analysed for a series of molecules where these effects are noticeable.

scholarly journals Direct observation of minibands in a twisted graphene/WS2 bilayer

2020 ◽  
Vol 6 (14) ◽  
pp. eaay6104 ◽  
Author(s):  
Søren Ulstrup ◽  
Roland J. Koch ◽  
Simranjeet Singh ◽  
Kathleen M. McCreary ◽  
Berend T. Jonker ◽  
...  
Keyword(s):  
Optical Measurements ◽  
Photoemission Spectroscopy ◽  
Transition Metal Dichalcogenide ◽  
Electron Hole ◽  
Final State ◽  
X Ray ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Electron Hole Pair ◽  
Twisted Graphene ◽  
Quasiparticle Band

Stacking two-dimensional (2D) van der Waals materials with different interlayer atomic registry in a heterobilayer causes the formation of a long-range periodic superlattice that may bestow the heterostructure with properties such as new quantum fractal states or superconductivity. Recent optical measurements of transition metal dichalcogenide (TMD) heterobilayers have revealed the presence of hybridized interlayer electron-hole pair excitations at energies defined by the superlattice potential. The corresponding quasiparticle band structures, so-called minibands, have remained elusive, and no such features have been reported for heterobilayers composed of a TMD and another type of 2D material. We introduce a new x-ray capillary technology for performing microfocused angle-resolved photoemission spectroscopy with a spatial resolution of ~1 μm, and directly observe minibands at certain twist angles in mini Brillouin zones (mBZs). We discuss their origin in terms of initial and final state effects by analyzing their dispersion in distinct mBZs.

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.

Synthesis and characterization of TiN / Ti / AISI 410 coatings

2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama
Keyword(s):  
Synthesis And Characterization ◽  
Photoemission Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Columnar Grains ◽  
Tin Thin Films ◽  
Steel Aisi ◽  
Interacting Surfaces ◽  
Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

Electronic Study of Pt-Ga Intermetallic Compounds Using X-Ray Photoemission Spectroscopy

1990 ◽  
Author(s):  
Young K. Kim ◽  
David K. Shuh ◽  
R. S. Williams ◽  
Larry P. Sadwick ◽  
Kang L. Wang
Keyword(s):  
Intermetallic Compounds ◽  
Photoemission Spectroscopy ◽  
X Ray

scholarly journals Electronic Structure of n-Cycloparaphenylenes Directly Observed by Photoemission Spectroscopy

2021 ◽  
Author(s):  
Kaname Kanai ◽  
Takuya Inoue ◽  
Takaya Furuichi ◽  
Kaito Shinoda ◽  
Takashi Iwahashi ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electronic Structures ◽  
Photoemission Spectroscopy ◽  
Cyclic Structure ◽  
Visible Absorption ◽  
X Ray ◽  
Inverse Photoemission

A series of n-cycloparaphenylenes ([n]CPP) were studied by ultraviolet photoemission, inverse photoemission, ultraviolet-visible absorption, and X-ray photoemission spectroscopy to detect their unique electronic structures. [n]CPP has a cyclic structure in...

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