Calculated Final-State Effects of the PMDA-ODA Polyimide X-ray Photoemission Spectrum

ABSTRACTWe have synthesized the dendrimer-Au hybrid nanoclusters by solution routes, and have carried out the various spectroscopic studies in order to investigate their electronic structures. From the line-shape analyses for Au 4f core-level photoemission spectra measured with hard X-ray synchrotron-radiation of Au nanoclusters with mean diameter of 2-3 nm stabilized outside the dendrimer, it is found that Au 4f core-level photoemission spectrum consists of two components. We attribute these components to interior Au atoms and surface Au atoms bonded to dendrimers. In the valence-band photoemission spectrum of these Au nanoclusters, we have observed the bandwidth narrowing of Au 5d-derived band compared to that of bulk Au crystallite. Moreover, we have observed the characteristic spectral feature in the vicinity of Fermi level due to the dynamic final-state effect in photoemission. We have also carried out the optical spectroscopic measurements of these Au nanoclusters. From these results, we discuss the electronic structures and interfacial properties of the dendrimer-Au hybrid nanoclusters.

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Fingerprinting shock-induced deformations via diffraction

Scientific Reports ◽

10.1038/s41598-021-88908-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Avanish Mishra ◽

Cody Kunka ◽

Marco J. Echeverria ◽

Rémi Dingreville ◽

Avinash M. Dongare

Keyword(s):

High Speed ◽

Shock Loading ◽

Dislocation Slip ◽

Line Profiles ◽

X Ray Diffraction ◽

Final State ◽

X Ray ◽

Shock Testing ◽

Local Pressures ◽

Deformation Modes

AbstractDuring the various stages of shock loading, many transient modes of deformation can activate and deactivate to affect the final state of a material. In order to fundamentally understand and optimize a shock response, researchers seek the ability to probe these modes in real-time and measure the microstructural evolutions with nanoscale resolution. Neither post-mortem analysis on recovered samples nor continuum-based methods during shock testing meet both requirements. High-speed diffraction offers a solution, but the interpretation of diffractograms suffers numerous debates and uncertainties. By atomistically simulating the shock, X-ray diffraction, and electron diffraction of three representative BCC and FCC metallic systems, we systematically isolated the characteristic fingerprints of salient deformation modes, such as dislocation slip (stacking faults), deformation twinning, and phase transformation as observed in experimental diffractograms. This study demonstrates how to use simulated diffractograms to connect the contributions from concurrent deformation modes to the evolutions of both 1D line profiles and 2D patterns for diffractograms from single crystals. Harnessing these fingerprints alongside information on local pressures and plasticity contributions facilitate the interpretation of shock experiments with cutting-edge resolution in both space and time.

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High-resolution cryo-EM structure of photosystem II reveals damage from high-dose electron beams

Communications Biology ◽

10.1038/s42003-021-01919-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Koji Kato ◽

Naoyuki Miyazaki ◽

Tasuku Hamaguchi ◽

Yoshiki Nakajima ◽

Fusamichi Akita ◽

...

Keyword(s):

Photosystem Ii ◽

Physiological State ◽

High Dose ◽

Final State ◽

X Ray ◽

Redox States ◽

X Ray Crystallography ◽

Cryo Electron Microscopy ◽

Redox Active ◽

Beam Damage

AbstractPhotosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure and some intermediate structures. However, these structures are in the crystalline state and its final state structure has not been solved. Here we analyzed the structure of PSII in solution at 1.95 Å resolution by single-particle cryo-electron microscopy (cryo-EM). The structure obtained is similar to the crystal structure, but a PsbY subunit was visible in the cryo-EM structure, indicating that it represents its physiological state more closely. Electron beam damage was observed at a high-dose in the regions that were easily affected by redox states, and reducing the beam dosage by reducing frames from 50 to 2 yielded a similar resolution but reduced the damage remarkably. This study will serve as a good indicator for determining damage-free cryo-EM structures of not only PSII but also all biological samples, especially redox-active metalloproteins.

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Initial and Final State Effects in the Ultraviolet and X-ray Photoelectron Spectroscopy (UPS and XPS) of Size-Selected Pdn Clusters Supported on TiO2(110)

The Journal of Physical Chemistry C ◽

10.1021/jp512263w ◽

2015 ◽

Vol 119 (11) ◽

pp. 6033-6046 ◽

Cited By ~ 35

Author(s):

F. Sloan Roberts ◽

Scott L. Anderson ◽

Arthur C. Reber ◽

Shiv N. Khanna

Keyword(s):

Photoelectron Spectroscopy ◽

Final State ◽

X Ray

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X-ray absorption near edge structures in cobalt oxides

Journal of Materials Research ◽

10.1557/jmr.1996.0285 ◽

1996 ◽

Vol 11 (9) ◽

pp. 2242-2256 ◽

Cited By ~ 24

Author(s):

T. Jiang ◽

D. E. Ellis

Keyword(s):

Wave Functions ◽

Site Symmetry ◽

Local Geometry ◽

Final State ◽

Cluster Technique ◽

Edge Structure ◽

X Ray ◽

Local Electronic Structure ◽

Edge Features ◽

X Ray Absorption

Theoretical studies have been made of K-edge x-ray absorption near edge structure (XANES) of Co in CoO, Co(OH)2, CoTiO3, Co3O4, and CoAl2O4. Correlations of experimental near edge features with site symmetry, local geometry, local electronic structure, i.e., atomic configuration, charge transfer, and backscattering from neighboring atomic potentials are interpreted. The self-consistent Discrete Variational Xa Method (DV-Xα) within an embedded cluster technique has been used to generate the crystal potential. A multiple scattering (MS) approach is then used to solve for the final state wave function. The ground state DV wave functions are analyzed in terms of the projected density of states, whereas the final state MS continuum wave functions are analyzed through the concept of photoelectron trapping time.

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X-ray photoemission spectrum of the III–VI layer compound GaTe in the region of the valence bands

Physica B+C ◽

10.1016/0378-4363(81)90215-1 ◽

1981 ◽

Vol 105 (1-3) ◽

pp. 59-64 ◽

Cited By ~ 7

Author(s):

F. Antonangeli ◽

A. Balzarotti ◽

E. Doni ◽

R. Girlanda ◽

V. Grasso ◽

...

Keyword(s):

Photoemission Spectrum ◽

Layer Compound ◽

X Ray ◽

Valence Bands

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

Physical Chemistry Chemical Physics ◽

10.1039/c9cp01569h ◽

2019 ◽

Vol 21 (18) ◽

pp. 9399-9406 ◽

Cited By ~ 1

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.

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Electronic band structure and the X-ray photoemission spectrum of UCu5In

Philosophical Magazine B ◽

10.1080/13642810208222949 ◽

2002 ◽

Vol 82 (18) ◽

pp. 1893-1906 ◽

Cited By ~ 7

Author(s):

G. Chelkowska ◽

J. A. Morkowski ◽

A. Szajek ◽

R. Tro

Keyword(s):

Band Structure ◽

Electronic Band Structure ◽

Photoemission Spectrum ◽

Electronic Band ◽

X Ray

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FDMX: extended X-ray absorption fine structure calculations using the finite difference method

Journal of Synchrotron Radiation ◽

10.1107/s1600577516001193 ◽

2016 ◽

Vol 23 (2) ◽

pp. 551-559 ◽

Cited By ~ 10

Author(s):

Jay D. Bourke ◽

Christopher T. Chantler ◽

Yves Joly

Keyword(s):

Fine Structure ◽

Energy Range ◽

Cross Sections ◽

Full Potential ◽

Final State ◽

X Ray ◽

Complete Representation ◽

Absorption Fine ◽

Energy Dependent ◽

X Ray Absorption

A new theoretical approach and computational package,FDMX, for general calculations of X-ray absorption fine structure (XAFS) over an extended energy range within a full-potential model is presented. The final-state photoelectron wavefunction is calculated over an energy-dependent spatial mesh, allowing for a complete representation of all scattering paths. The electronic potentials and corresponding wavefunctions are subject to constraints based on physicality and self-consistency, allowing for accurate absorption cross sections in the near-edge region, while higher-energy results are enabled by the implementation of effective Debye–Waller damping and new implementations of second-order lifetime broadening. These include inelastic photoelectron scattering and, for the first time, plasmon excitation coupling. This is the first full-potential package available that can calculate accurate XAFS spectra across a complete energy range within a single framework and without fitted parameters. Example spectra are provided for elemental Sn, rutile TiO2and the FeO6octahedron.

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