Search results for "electron spectroscopy"
showing 10 items of 525 documents
Titanium dioxide surface stoichiometry and ordering studied by resonant photoemission spectroscopy
2005
Abstract The electronic structure of titanium dioxide surfaces having undergone different preparations leading to different stoichiometries and crystallinities has been studied using resonant photoemission spectroscopy. Valence band photoemission spectra through the Ti 3p–3d/4s absorption edge between 45 and 55 eV were measured and allowed a characterization of defects present at the surface as well as of the quality of the surface organization. Indeed, from the comparison of the resonance results obtained for each kind of surface with the LEED patterns on the one hand and the corresponding Ti 2p core level lines on the other hand, it was evidenced that the high binding energy part of the v…
White Light-Emitting Electrochemical Cells Based on the Langmuir–Blodgett Technique
2014
Light-emitting electrochemical cells (LECs) showing a white emission have been prepared with Langmuir-Blodgett (LB) films of the metallosurfactant bis[2-(2,4-difluorophenyl)pyridine][2-(1-hexadecyl-1H-1,2,3-triazol-4-yl)pyridine]iridium(III) chloride (1), which work with an air-stable Al electrode. They were prepared by depositing a LB film of 1 on top of a layer of poly(N,N'-diphenyl-N,N'-bis(4-hexylphenyl)-[1,1'-biphenyl]-4,4'-diamine (pTPD) spin-coated on indium tin oxide (ITO). The white color of the electroluminescence of the device contrasts with the blue color of the photoluminescence of 1 in solution and within the LB films. Furthermore, the crystal structure of 1 is reported togeth…
Photoluminescent hybrid nanomaterials from modified halloysite nanotubes
2018
The synthesis of photoluminescent nanomaterials based on halloysite nanotubes is described. The obtained hybrid was characterized by means of TGA, FT-IR, DLS and XPS measurements; in addition its morphology was imaged by TEM and HR-TEM. The HNT hybrid also exhibited photoluminescent properties, both in solution and in the solid state, and white-light emission (0.24, 0.36; CIE coordinates) was observed. This work could be pioneering as a new strategy for manufacturing both LEDs and fluorescent tags based on HNT nanomaterials. © 2018 The Royal Society of Chemistry.
Surface investigation and aluminum oxide estimation on test filters for the ATHENA X-IFU and WFI detectors
2016
The ATHENA mission provides the demanded capabilities to address the ESA science theme "Hot and Energetic Universe". Two complementary instruments are foreseen: the X-IFU (X-ray Integral Field Unit) and WFI (Wide Field Imager). Both the instruments require filters to avoid that the IR radiation heats the X-IFU cryogenic detector and to protect the WFI detector from UV photons. Previous experience on XMM filters recommends to employ bilayer membrane consisting of aluminum deposited on polyimide. In this work, we use the X-ray Photoelectron Spectroscopy (XPS) to quantify the native aluminum oxide thickness that affects the spectral properties of the filter. The estimation of the oxide thickne…
Palladium local structure of La1-xSrxCo1-yFey-0.03Pd0.03O3-δperovskites synthesized using a one pot citrate method
2014
Nanostructured La1-xSrxCo1-yFey-0.03Pd0.03O3-δ(LSCF-Pd) perovskites with fixed La-Sr composition (x = 0.4) and two different Fe contents (y = 0.2 and 0.8) were successfully synthesized using a one pot citrate method starting from nitrates of the metal cations. Pd-free La1-xSrxCo1-yFeyO3-δ(LSCF) systems were prepared for comparison. LSCF powders were calcined at 1300 °C and characterized by XRD and Rietveld refinement, EXAFS, XPS, TPR analyses. Promotion of La0.6Sr0.4Co0.8Fe0.2O3-δand of La0.6Sr0.4Co0.2Fe0.8O3-δby incorporation of palladium was evidenced by solving the local environment of Pd using EXAFS spectroscopy. XPS analyses, in agreement with TPR measurements, demonstrated an inc…
Interference Effects in Photodetachment of F- in a Strong Circularly Polarized Laser Pulse
2007
A numerical simulation of photodetachment of F{sup -} by a circularly polarized laser pulse has been accomplished by using a Keldysh-type approach. The numerical results are in agreement with measurements of photoelectron energy spectra recently reported in the literature. The features exhibited by the spectra are traced back to quantum interference effects, in the same spirit as in a double-slit experiment in the time doma0008.
Influence ofsp−dhybridization on the electronic structure of Al-Mn alloys
2008
The influence of $sp\text{\ensuremath{-}}d$ hybridization on the electronic structure of different Al-Mn alloys has been studied by photoelectron spectroscopy. Experimental evidence of a pseudogap in a crystalline binary Hume-Rothery alloy is provided. The pseudogap varies systematically with Mn concentration. The $sp\text{\ensuremath{-}}d$ hybridization alone, even in the absence of Hume-Rothery mechanism, can produce the pseudogap. Existence of the pseudogap, suppression of the $\mathrm{Mn}\phantom{\rule{0.2em}{0ex}}2p$ satellite, and decrease in the Doniach-\ifmmode \check{S}\else \v{S}\fi{}unji\ifmmode \acute{c}\else \'{c}\fi{} asymmetry parameter are the consequences of the $sp\text{\e…
Positrons and Electrons Emitted in Elastic and Dissipative Heavy Ion Collisions
1987
The main research line of the Tori group is the study of the reaction dynamics of dissipative collisions between heavy ions ia positron and electron spectroscopy. The last five years since the Lahnstein-Conference1 are marked for our group by the installation of a new experimental device for detecting positrons and electrons emitted in these collisions, the so-called Tori spectrometer2. The first part of this report is devoted therefore to describe the main characteristics of this apparatus.
In-beam spectroscopy of $^{253,254}$No
2002
In-beam conversion electron spectroscopy experiments have been performed on the transfermium nuclei 253,254No using the conversion electron spectrometer SACRED in nearly collinear geometry in conjunction with the gas-filled separator RITU at the University of Jyvaskyla. The experimental setup is discussed and the spectra are compared to Monte Carlo simulations. The implications for the ground-state configuration of 253No are discussed.
Iodine on a magnetized iron film evidence for a magnetic coupling
1993
Abstract Spin-resolved photoelectron spectra of iodine chemisorbed on a magnetized iron (110) surface have been taken using unpolarized VUV light. The partial spin spectra reveal the I 5p x and 5p z signals being split by up to 0.35 eV. This exchange splitting occurs due to hybridization of adsorbate and substrate bands as a consequence of the chemical bond of the halogen atoms to the iron surface.