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| 2. |
- Butorin, S. M., et al.
(författare)
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Low-Energy d-d Excitations in MnO Studied by Resonant X-ray Fluorescence Spectroscopy
- 1997
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Ingår i: Advanced Light Source. - Berkely : Ernest Orlando Lawrence Berkeley National Laboratory University of California Berkeley, California. ; , s. 135-136
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. (see other abstracts in this Annual Report). In the present abstract we focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means ofresonant electronic X-ray Raman scattenng....
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| 3. |
- Butorin, S. M., et al.
(författare)
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Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy
- 1996
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 54, s. 4405-4408
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Tidskriftsartikel (refereegranskat)abstract
- We measured the Mn Lα,β x-ray fluorescence spectra of MnO excited by selected photon energies near the L2,3 absorption edges. The resulting resonant inelastic x-ray scattering spectra probe low-lying electronic excited states, due to dd and charge-transfer excitations. Using a two-step model and a purely atomic approximation, we reproduce both energies and varying intensities of dd excitations relative to the electronic recombination peak. Our results show that strongly varying line shapes in resonant x-ray emission need not be due to channel interference effects.
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| 4. |
- Butorin, S. M., et al.
(författare)
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Resonant inelastic soft X-ray scattering at the 4d edge of Ce-based heavy fermion materials
- 1999
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - 0368-2048 .- 1873-2526. ; 101-103, s. 783-786
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Tidskriftsartikel (refereegranskat)abstract
- Resonant X-ray scattering measurements were performed on CeB6, CeAl, γ-Ce, and α-Ce at various incident-photon energies near the Ce 4d threshold. A pronounced inelastic scattering structure which has 4f character is observed at about 4 eV below the elastic peak. The structure shows a distinct resonant behavior as well as a dependence on the degree of 4f hybridization and can therefore be attributed to charge-transfer excitations to the 4f0 state. The intensity of the elastic peak increases when going from the systems with low Kondo temperature TK to those with high TK which is consistent with a Kondo scale behavior. By analyzing the scattering data, a controversial issue on the validity of a single-impurity Anderson model in heavy-fermion materials is addressed.
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| 5. |
- Butorin, S. M., et al.
(författare)
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Resonant inelastic soft-x-ray scattering from valence-band excitations in 3d0 compounds
- 1997
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 55, s. 4242-4249
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Tidskriftsartikel (refereegranskat)abstract
- Ti and Mn Lα,Β x-ray fluorescence spectra of FeTiO3 and KMnO4 were measured with monochromatic photon excitation on selected energies across the L2,3 absorption edges. The resulting inelastic x-ray-scattering structures and their changes with varying excitation energies are interpreted within the framework of a localized, many-body approach based on the Anderson impurity model, where the radiative process is characterized by transitions to low-energy interionic-charge-transfer excited states. Sweeping the excitation energy through the metal 2p threshold enhances the fluorescence transitions to the antibonding states pushed out of the band of continuous states due to strong metal 3d–ligand 2p hybridization and matching the low-photon-energy satellites in the spectra. Based on the energy position of these charge-transfer satellites with respect to the recombination peak the effective metal 3d–ligand 2p hybridization strength in the ground state of the system can be estimated directly from the experiment.
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| 6. |
- Guo, J. H., et al.
(författare)
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Characterization of undulator radiation at MAXII using a soft X-ray fluorescence spectrometer
- 1999
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0168-9002. ; 431:1, s. 285-293
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Tidskriftsartikel (refereegranskat)abstract
- A grazing-incidence grating spectrometer has been used for the investigation of the undulator radiation from beamline 411 at MAX-lab. The direct detection of undulator light is expected to obtain the information of the quality of the undulator. Regular undulator radiation and some higher harmonics were observed. The effects of electronic beam coupling and Landau cavities have been studied. The experiment presents an easy and quick method to characterize the undulator radiation before the permanent monochromator is installed.
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| 7. |
- Jensen, B. N., et al.
(författare)
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Design and performance of a spherical grating monochromator used at MAX I
- 1997
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0168-9002. ; 394:1-2, s. 243-250
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Tidskriftsartikel (refereegranskat)abstract
- We report on the performance of a grazing incidence spherical grating monochromator installed at MAX I and designed to cover the photon energy range from about 15-200 eV with high resolving power. It is intended mainly for angle-resolved photoemission work. Therefore, both refocusing optics, to obtain a small spot size at the sample, and a higher order light suppressor, to reduce the content of higher orders, have been incorporated in the design. The theoretically calculated energy resolution is presented and compared to the resolution obtained in photoabsorption measurements of gas-phase He, Ne, Kr, Xe, and N2. The possibility to reduce the influence of higher orders is illustrated by photoemission data collected on Si (100). The experimental results show that the monochromator fulfills the expected design goals.
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| 8. |
- Magnuson, Martin, 1965-, et al.
(författare)
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The electronic structure of polyaniline and doped phases studied by soft X-ray absorption and emission spectroscopies
- 1999
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 111:10, s. 4756-4761
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the conjugated polymer, polyaniline, has been studied by resonant and nonresonant soft x-ray emission spectroscopy using synchrotron radiation for the excitation. The measurements were made on polyaniline and a few doped (protonated) phases for both the carbon and nitrogen contents. The resonant x-ray emission spectra show depletion of the π electron bands due to the selective excitation which enhances the effect of symmetry selection rules. The valence band structures in the x-ray emission spectra attributed to the π bands show unambiguous changes of the electronic structure upon protonation. By comparing to x-ray absorption measurements, the chemical bonding and electronic configuration is characterized.
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