X-ray Emission Spectroscopy (x-ray + emission_spectroscopy)

Distribution by Scientific Domains


Selected Abstracts


Picosecond Time-Resolved X-Ray Emission Spectroscopy: Ultrafast Spin-State Determination in an Iron Complex,

ANGEWANDTE CHEMIE, Issue 34 2010
György Vankó Dr.
Ultraschnelle Spinsonde: Photoangeregtes [Fe(bpy)3]2+ (bpy=2,2,-Bipyridin) zeigt kurzlebige Strukturänderungen, die einer Anregung in einen High-Spin-Zustand entsprechen. In diesem Zustand wurde der Spin von FeII durch spinsensitive ultraschnelle Röntgenemissionsspektroskopie mit harter Röntgenstrahlung zu S=2 bestimmt. [source]


Direct Detection of Oxygen Ligation to the Mn4Ca Cluster of Photosystem II by X-ray Emission Spectroscopy,

ANGEWANDTE CHEMIE, Issue 4 2010
Yulia Pushkar Dr.
O im Blick: Mn-K,2,5 - und -K,,,-Emissionsspektren entstehen durch Übergänge von den Ligand-2s- und -2p-Schalen der Metallkomplexe in die 1s-Metallniveaus. Auf diese Weise konnten die O-Liganden des Mn4Ca-Clusters untersucht werden, der die photosynthetische Wasserspaltung katalysiert, was erstmals den direkten Nachweis der verbrückenden Oxogruppen an Mn ermöglichte. [source]


X-ray emission spectroscopy with a laser-heated diamond anvil cell: a new experimental probe of the spin state of iron in the Earth's interior

JOURNAL OF SYNCHROTRON RADIATION, Issue 5 2005
Jung-Fu Lin
Synchrotron-based X-ray emission spectroscopy (XES) is well suited to probing the local electronic structure of 3d transition metals such as Fe and Mn in their host phases. The laser-heated diamond anvil cell technique is uniquely capable of generating ultra-high static pressures and temperatures in excess of 100,GPa and 3000,K. Here X-ray emission spectroscopy and X-ray diffraction have been interfaced with the laser-heated diamond cell for studying the electronic spin states of iron in magnesiowüstite-(Mg0.75,Fe0.25)O and its crystal structure under lower-mantle conditions. X-ray emission spectra of the ferrous iron in a single crystal of magnesiowüstite-(Mg0.75,Fe0.25)O indicate that a high-spin to low-spin transition of ferrous iron occurs at 54 to 67,GPa and 300,K and the ferrous iron remains in the high-spin state up to 47,GPa and 1300,K. This pilot study points to the unique capability of the synchrotron-based XES and X-ray diffraction techniques for addressing the issue of electronic spin transition or crossover in 3d transition metals and compounds under extreme high- P,T conditions. [source]


Theory of resonant X-ray emission spectroscopy

JOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001
A. Kotani
A short review is presented of recent topics in resonant X-ray emission spectroscopy (RXES), especially of the polarization dependence of RXES in d and f electron systems. Polarization-dependent RXES provides important information on the symmetry of electronic states. A scattering-angle dependence in the fluorescence yield of rare-earth metals, RXES in polarized and depolarized configurations of TiO2, and the magnetic circular dichroism in RXES of ferromagnetic systems are discussed together with typical experimental data. [source]


Electronic structure analyses of BN network materials using high energy-resolution spectroscopy methods based on transmission electron microscopy

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 7 2006
M. Terauchi
Abstract Electronic structures of boron-nitride (BN) nanotubes and a BN cone-structure material were studied by using a high energy-resolution electron energy-loss spectroscopy (EELS) microscope. A trial of the whole electronic structure study of hexagonal BN (h-BN), which consists of flat BN honeycomb layers, was conducted by a combination of EELS and X-ray emission spectroscopy (XES) based on transmission electron microscopy (TEM) (TEM-EELS/XES). The , and ,+, plasmon energies of BN nanotubes (BNT) were smaller than those of h-BN. The ,+, energy was explained by the surface plasmon excitation. The spectrum of a two-wall BNT of 2.7 nm in diameter showed a new spectral onset at 4 eV. The valence electron excitation spectra obtained from the tip region of the BN cone with an apex angle of 20° showed similar intensity distribution with those of BNTs. The B K-shell electron excitation spectra obtained from the bottom edge region of the BN cone showed additional peak intensity when compared with those of h-BN and BNT. The B K-shell electron excitation spectra and B K-emission spectra of h-BN were compared with a result of a LDA band calculation. It showed that high symmetry points in the band diagram appear as peak and/or shoulder structures in the EELS and XES spectra. Interband transitions appeared in the imaginary part of the dielectric function of h-BN experimentally obtained were assigned in the band diagram. The analysis also presented that the LDA calculation estimated the bandgap energy smaller than the real material by an amount of 2 eV. Those results of TEM-EELS/XES analysis presented that high energy-resolution spectroscopy methods combined with TEM is a promising method to analyze whole electronic structures of nanometer scale materials. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source]


Soft X-ray emission spectroscopy of low-dimensional SiO2/Si interfaces after Si+ ion implantation and ion beam mixing

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
D. A. Zatsepin
Abstract An X-ray Si L2,3 -emission spectroscopy study of a SiO2/n-Si heterostructure containing a thin oxide layer of d,=,20,nm thickness implanted by Si+ ions with an energy 12,keV is reported. The maximum concentration of implanted Si+ ions is located close to the SiO2,Si interface at a depth of 18,nm leading to an ion-beam mixed SiO2/Si interface layer in this region, consisting of a non-stoichiometric SiOx matrix. The possible mechanisms of these processes are discussed by atomic collision cascades (knocking-off and knocking-on processes) during ion implantation, associated by partial phase separation into silicon precipitates and SiO2. [source]


Characterization of Fe 3d states in CuFeS2 by resonant X-ray emission spectroscopy

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009
Katsuaki Sato
Abstract Resonant X-ray emission spectroscopy (RXES) experiments were carried out in a single crystal of chalcopyrite CuFeS2, an antiferromagnetic semiconductor with a golden lustre, to unravel the overlapping d,d and charge-transfer transitions extending well above the absorption edge, which cannot be observed by conventional optical absorption experiments. The observed RXES spectra have been analyzed by means of cluster-model calculation with configuration interaction, which leads to the conclusion that CuFeS2 is a Haldane,Anderson insulator with a negative value of charge transfer energy, , = ,3 eV. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]