A5008070942- Electron and X-Ray Spectroscopy Techniques
- Molecular Junctions and Nanostructures
- Magnetic and transport properties of perovskites and related materials
- Ion-surface interactions and analysis
- Surface and Thin Film Phenomena
- Advanced Condensed Matter Physics
- Electrocatalysts for Energy Conversion
- Quantum Dots Synthesis And Properties
- Advanced Chemical Physics Studies
- Diamond and Carbon-based Materials Research
- X-ray Spectroscopy and Fluorescence Analysis
- Thin-Film Transistor Technologies
- Semiconductor materials and devices
- Electrochemical Analysis and Applications
- Electronic and Structural Properties of Oxides
- Rare-earth and actinide compounds
- Silicon Nanostructures and Photoluminescence
- Fullerene Chemistry and Applications
- Metal and Thin Film Mechanics
- Nuclear Physics and Applications
- Multiferroics and related materials
- Catalytic Processes in Materials Science
- Copper-based nanomaterials and applications
- Advancements in Solid Oxide Fuel Cells
- Radioactive element chemistry and processing
DASA (Brazil)
2024
Bariloche Atomic Centre
2011-2021
Comisión Nacional de Energía Atómica
2009-2021
Balseiro Institute
2010-2021
Consejo Nacional de Investigaciones Científicas y Técnicas
2009-2021
Universidad Nacional de Cuyo
2001-2021
Centro Científico Tecnológico - San Juan
2002-2021
Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona
2014
University of Warwick
2007
Daresbury Laboratory
2007
We studied the relation between electronic structure and phsyiscal properties of ${\mathrm{SrFe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{O}}_{3}.$ The main technique used in study was Fe $2p,$ Co O $1s$ x-ray absorption spectroscopy. experimental spectra were analyzed terms configuration-interaction cluster model calculation. analysis shows that both ${\mathrm{SrFeO}}_{3}$ ${\mathrm{SrCoO}}_{3}$ are negative-charge transfer regime (this means their ground states mostly covalent contain...
We studied the changes in electronic structure of ${\mathrm{LaNiO}}_{3\ensuremath{-}\ensuremath{\delta}}$ across metal-insulator transition. The technique used study was mainly $\mathrm{O} 1s$ x-ray absorption spectroscopy (XAS). experimental spectrum ${\mathrm{LaNiO}}_{3.00}$ analyzed terms a cluster-model calculation. presents sharp peak at threshold that corresponds to ${3d}^{8}L\stackrel{\ensuremath{\rightarrow}}{̱}c̱{3d}^{9}$ transitions. Analysis this indicates charge carriers contain...
We have measured energy spectra of electrons resulting from collisions 0.4-0.5-keV ${\mathrm{Ne}}^{+}$ with solid targets Mg, Al, and Si. found only two peaks, in the electron-energy range 20---30 eV, corresponding to autoionization ${\mathrm{Ne}}^{**}$ $2{p}^{4}(^{3}P,^{1}D)3{s}^{2}$ states. Unlike gasphase collisions, peak $^{3}P$ core is most intense. interpret our results a model involving reflection excitation projectile its collision surface. The mechanism similar that gas-phase...
Heterogeneous photocatalytic reduction of As(V) and As(III) at different concentrations over TiO(2) under UV light in deoxygenated aqueous suspensions is described. For the first time, As(0) was unambiguously identified together with arsine (AsH(3)) as reaction products. requires presence an electron donor (methanol present case) takes place through hydroxymethyl radical formed from methanol oxidation by holes or hydroxyl radicals. On contrary, direct TiO(2)-conduction band electrons....
We present a study of amorphous hydrogenated silicon-nitrogen alloys (a-${\mathrm{SiN}}_{\mathit{x}}$:H, 0\ensuremath{\le}x1.5) prepared by the rf reactive sputtering method. By combining results x-ray photoemission spectroscopy, electron-energy-loss and optical absorption, all atom bond densities kind mean number nearest neighbors Si N atoms are determined. For x1, Si-N bonds increase at expense Si-Si bonds; almost fully coordinated three atoms, whereas have N, H, other as neighbors....
The electronic structure of highly under-coordinated Rh atoms, namely adatoms and ad-dimers, on homo-metallic surfaces has been probed by combining high-energy resolution core level photoelectron spectroscopy density functional theory calculations. Rh3d5/2 shifts are shown to be proportional the number nearest-neighbours (n = 3, 4 5). A more refined analysis shows that energy position different components is correlated with calculated changes individual inter-atomic bond length d-band...
The preparation and thermal stability of benzenethiol benzeneselenol self-assembled monolayers (SAMs) grown on Au(111) have been investigated by electrochemical experiments high-resolution photoemission spectroscopy. Both techniques confirm the formation with high packing densities (θ = 0.27-0.29 ML) good degrees order in both cases. Despite many similarities between two SAMs, desorption is distinctly different: whereas SAM desorbs a single steplike process, occurs much lower activation...
Angle-resolved photoemission data from Al(001) taken with photon energies up to several hundred electron volts show an unexpected surface sensitivity at high energies. The state the center of Brillouin zone can be clearly observed higher than 700 eV. bulk intensity ratio appears increase energy, despite longer inelastic mean-free path electrons and increased vibrational amplitude surface. We explain this surprising behavior by considering effect phonon excitation in event.
We investigated the formation and stability of layers methylthiolate prepared on Au(111) surface by method immersion in an ethanolic solution dimethyl disulfide (DMDS). The species were characterized electrochemical reductive desorption high-resolution photoelectron spectroscopy. Both techniques confirmed a monolayer at short times (around 1 min). As time increased, experiments showed disappearance current peak appearance ca. −0.9 V which was attributed to sulfur species. At long times, XPS...
In this work, the electrochemical formation of alkanethiolate self-assembled monolayers (SAMs) on Ni(111) and polycrystalline Ni surfaces from alkanethiol-containing aqueous 1 M NaOH solutions was studied by combining Auger electron spectroscopy (AES), X-ray photoelectron (XPS), techniques, density functional theory (DFT) calculations. Results show that alkanethiolates adsorb concurrent with NiO electroreduction. The resulting surface coverage depends applied potential hydrocarbon chain...
We have studied atomiclike Auger peaks appearing in the electron energy spectra of solids under low-energy heavy-ion bombardment. These are usually associated with transitions either projectiles or target atoms. A controversy exists on whether these excited atoms decay inside outside solid. Simple considerations show that an ejected from atom placed solid surface, referred to Fermi level, should depend work function. observed this correlation three different cases, which shows such correspond decays
The structural phases formed by atomic sulfur on Au(111) due to reaction with molecular S2 have been investigated qualitative low-energy electron diffraction (LEED), scanning tunneling microscopy, and normal incidence X-ray standing wavefield absorption (NIXSW) combined photoelectron spectroscopy (XPS). Three are identified increasing coverage, namely, a newly (5 × 5) phase, ( )R30° “complex” phase. LEED pattern having the appearance of “split-spot” pattern, is interpreted in terms local...
We report the magnetic properties of antiferromagnetic Cr2O3 from bulk material down to 6 nm nanoparticles. have found a decrease in lattice parameters and cell volume when size diminishes. On contrary, anisotropy constant, Keff, shows nonmonotonic behavior. The Keff decreases its value, minimum near ϕ∼30 displays an important increase for smaller sizes. analyzed dependence terms magnetocrystalline surface contributions, we fitted evolution on basis phenomenological model taking into account...
We studied the electronic structure of ${\mathrm{CaMnO}}_{x}$ $(2.66<~x<~3.00)$ using x-ray photoemission and O $1s$ x-ray-absorption spectroscopy. Analyzing spectra two end members with configuration-interaction cluster model, we have determined all main parameters structure. found that ground states ${\mathrm{CaMnO}}_{2.5}$ ${\mathrm{CaMnO}}_{3}$ are highly covalent, approximately same number ligand holes per oxygen atom: 0.22--0.23. The separations between Mn $3d$ bands closest to Fermi...
Through a systematic analysis based on DFT calculations, we have studied the adsorption of S atoms Au(111) at low and intermediate coverages (θ ≤ 1/3). Our calculations predict ground state structures characterized by two periodicities: (5 × 5) (√3 √3)R30°. In line with experiments, periodicity seems to dominate in much larger coverage range than √3)R30° one, which should be only observable narrow window close 1/3. addition, our results unambiguously reveal crucial role S-induced substrate...