Showing papers by "Gérard Tourillon published in 1989"
TL;DR: In this paper, high pressure properties of krypton were investigated by energy-dispersive extended x-ray absorption fine-structure spectroscopy in a diamond anvil cell at room temperature.
Abstract: High-pressure properties of krypton were investigated by energy-dispersive extended x-ray absorption fine-structure spectroscopy in a diamond anvil cell at room temperature. The equation of state agrees very well with x-ray diffraction data. The pressure dependence of the Debye-Waller factor was determined and compared with calculations using pair potentials. The analysis of the x-ray absorption near-edge structure part of the spectrum shows the possibility of measuring the pressure in bubbles of krypton implanted in metallic matrices.
47 citations
TL;DR: In this article, the oscillator strength for C 1s excitation of azulene in the gas phase has been derived from electron energy loss spectra recorded under dipole-dominated scattering conditions.
Abstract: The oscillator strength for C 1s excitation of azulene in the gas phase has been derived from electron energy loss spectra recorded under dipole-dominated scattering conditions. The spectral features are assigned to C 1s excitations to {pi}* and {sigma}* valence unoccupied orbitals. The azulene C 1s spectrum is compared to that of naphthalene and the differences are related primarily to changes in the {pi}* orbital energies. The near-edge X-ray absorption fine structure (NEXAPS) spectra of thin films of polyazulene electrochemically deposited on Pt are also reported. The orientation dependence of the C 1s spectrum of very thin films assists spectral interpretation. Changes in the C 1s NEXAFS spectrum associated with electrochemical doping to form a conducting state of the polymer are discussed in terms of the probable conduction mechanism in doped polyazulene.
25 citations
TL;DR: In this paper, the evolution of the Cu K edge upon changing in situ the oxygen stoichiometry of Y1Ba2Cu3O7−δ was studied by using X-ray absorption spectroscopy (XAS) in dispersive mode.
9 citations
TL;DR: In this article, the authors proposed a time-resolved X-ray Absorption Spectroscopy (TAS) with extreme energy resolution and energy scale stability taking full advantage of the strong correlation between the stereochemical environment of the absorbing atom and the exact shape and position of the absorption edge.
Abstract: X-ray Absorption Spectroscopy has undergone a great theoretical and experimental development in the last years. This technique has proved to be a powerful tool in elucidating huge number of questions in materials science. Great interest exists in time-resolved experiments achieved with extreme energy resolution and energy scale stability taking full advantage of the strong correlation between the stereochemical environment of the absorbing atom and the exact shape and position of the absorption edge.
8 citations
TL;DR: In this article, the valence states of cations inside four high Tc thallium superconductors have been investigated by X-ray absorption spectroscopy at LIII, LI and copper K-edges.
Abstract: The valence states of cations inside four high Tc thallium superconductors have been investigated by X-ray absorption spectroscopy at thallium LIII, LI and copper K-edges. The thallium ions are observed on LIII and LI edges in the Tl(III) valence state (empty 6s levels) in spite of large Tl-O distances in the (a, b) plane of the structure as deduced from X-ray diffraction. The presence of two types of Tl-O distances have been well established on XANES spectra and the F.T. of EXAFS have shown the presence of two very short Tl-O bonds (2.03 A). The copper K-edges are characterized by the absence of Cu(I) state (3d10 line).
7 citations
3 citations
01 Jan 1989
TL;DR: In this paper, a combined detector has been designed at LURE which yields spectra in transmission, electron and fluorescence modes, which offers, compare to the surface EXAFS technique, several advantages : i) possibility of studying directly thick samples without any specific preparation, ii) simplicity of the technology which does not require ultra high vacuum and iii) high sensitivity due to the large solid angle collection.
Abstract: The electron yield at atmospheric pressure for X ray absorption spectroscopy is a new technique able to study the very top surface of thick samples in real environments. A combined detector has been designed at LURE which yields spectra in transmission, electron and fluorescence modes. This method offers, compare to the surface EXAFS technique, several advantages : i) possibility of studying directly thick samples without any specific preparation, ii) simplicity of the technology which does not require ultra-high vacuum and iii) high sensitivity due to the large solid angle collection. The probed thickness with this configuration is typically of the order of 300-500A which means that thin films, implanted materials or interfaces can be studied ; preliminary results on such systems are reported.
2 citations
TL;DR: In this article, high pressure properties of krypton were investigated by energy-dispersive extended x-ray absorption fine-structure spectroscopy in a diamond anvil cell at room temperature.
Abstract: High-pressure properties of krypton were investigated by energy-dispersive extended x-ray absorption fine-structure spectroscopy in a diamond anvil cell at room temperature. The equation of state agrees very well with x-ray diffraction data. The pressure dependence of the Debye-Waller factor was determined and compared with calculations using pair potentials. The analysis of the x-ray absorption near-edge structure part of the spectrum shows the possibility of measuring the pressure in bubbles of krypton implanted in metallic matrices.
2 citations
2 citations
TL;DR: In this paper, the technique d'absorption X en mode dispersif associee a un detecteur a localisation (barrette de photodiodes) permet d'obtenir des spectres in un temps minimum de 4 ms.
Abstract: La technique d'absorption X en mode dispersif associee a un detecteur a localisation (barrette de photodiodes) permet d'obtenir des spectres en un temps minimum de 4 ms. De nombreuses etudes cinetiques ont ete realisees avec ce systeme. Deux exemples sont developpes: oxydoreduction d'une electrode d'hydroxyde de nickel et oxygenation et desoxygenation des supraconducteurs haute temperature
1 citations