| 1. |
- Magnuson, Martin, et al.
(författare)
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Resonant Auger spectroscopy at the L2,3 shake-up thresholds as a probe of electron correlation effects in nickel
- 1998
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 58:7, s. 3677-3681
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Tidskriftsartikel (refereegranskat)abstract
- The excitation energy dependence of the three-hole satellites in the L3-M45M45 and L2-M45M45 Auger spectra of nickel metal has been measured using synchrotron radiation. The satellite behavior in the nonradiative emission spectra at the L3 and L2 thresholds is compared and the influence of the Coster-Kronig channel explored. The three-hole satellite intensity at the L3 Auger emission line reveals a peak structure at 5 eV above the L3 threshold attributed to resonant processes at the 2p53d9 shake-up threshold. This is discussed in connection with the 6-eV feature in the x-ray-absorption spectrum.
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| 2. |
- Magnuson, Martin, 1965-, et al.
(författare)
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Resonant inelastic soft X-ray scattering spectra at the nitrogen and carbon K-edges of poly(pyridine-2,5-diyl)
- 1999
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - 0368-2048 .- 1873-2526. ; 101-103, s. 573-578
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Tidskriftsartikel (refereegranskat)abstract
- Resonant inelastic scattering measurements of the conjugated polymer, poly(pyridine-2,5-diyl) have been performed at the nitrogen and carbon K-edges using synchrotron radiation. For comparison, molecular orbital calculations of the spectra have been carried out with the repeat unit as a model molecule of the polymer chain. The resonant emission spectra show depletion of the π electron bands which is consistent with symmetry selection and momentum conservation rules. The depletion is most obvious in the resonant inelastic scattering spectra of carbon while the nitrogen spectra are dominated by lone pair n orbital emission of σ symmetry and are less excitation energy dependent. By comparing the measurements to calculations an isomeric dependence of the resonant spectra is found giving preference to two of the four possible isomers in the polymer.
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| 3. |
- Magnuson, Martin, 1965-, et al.
(författare)
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The electronic structure of poly(pyridine-2,5-diyl) investigated by soft X-ray absorption and emission spectroscopies
- 1998
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Ingår i: Chemical Physics. - 0301-0104 .- 1873-4421. ; 237:3, s. 295-304
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the poly-pyridine conjugated polymer has been investigated by resonant and non-resonant inelastic X-ray scattering and X-ray absorption spectroscopies using synchrotron radiation. The measurements were made for both the carbon and nitrogen contents of the polymer. The analysis of the spectra has been carried out in comparison with molecular orbital calculations taking the repeat-unit cell as a model molecule of the polymer chain. The simulations indicate no significant differences in the absorption and in the non-resonant X-ray scattering spectra for the different isomeric geometries, while some isomeric dependence of the resonant spectra is predicted. The resonant emission spectra show depletion of the electron bands in line with symmetry selection and momentum conservation rules. The effect is most visual for the carbon spectra; the nitrogen spectra are dominated by lone pair n orbital emission of symmetry and are less frequency dependent.
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| 4. |
- Magnuson, Martin, 1965-, et al.
(författare)
-
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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| 5. |
- Weinelt, M., et al.
(författare)
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Resonant Photoemission at the 2p Edges of Ni: Resonant Raman and Interference Effects
- 1997
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 78:5, s. 967-970
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Tidskriftsartikel (refereegranskat)abstract
- Unambiguous evidence for resonant photoemission in Ni is presented. Interference effects are identified at the 2p edges for the valence band and the 6 eV satellite. A rapid transition from a resonant Raman to an Auger-like regime shows that the core-excited states above threshold are not localized enough to significantly enhance the photoemission intensity, implying a large fraction of incoherent intensity. The results indicate that the appearance of interference effects does not require strong localization of the intermediate state.
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| 6. |
- Weinelt, M, et al.
(författare)
-
Resonant photoemission at the 2p edges of Ni: Resonant Raman and interference effects
- 1997
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Ingår i: PHYSICAL REVIEW LETTERS. - 0031-9007. ; 78:5, s. 967-970
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Unambiguous evidence for resonant photoemission in Ni is presented. Interference effects are identified at the 2p edges for the valence band and the 6 eV satellite. A rapid transition from a resonant Raman to an Auger-like regime shows that the core-excit
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| 7. |
- Magnuson, M., et al.
(författare)
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Angular-dependent resonant-photoemission processes at the 2p thresholds in nickel metal
- 1999
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 60:4, s. 2436-2440
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Tidskriftsartikel (refereegranskat)abstract
- Angle-resolved valence-band resonant-photoemission of nickel metal has been measured close to the 2p core-level thresholds with synchrotron radiation. The well-known 6-eV correlation satellite has an intensity enhancement of about two orders of magnitude at resonance. The angular dependence of the photoemission intensity has been studied as function of photon energy and provides unambiguous evidence for interference effects all the way up to the resonance maximum. The observation of different angular asymmetries, β, for the valence band and the satellite is discussed in connection to the origin of the resonant-photoemission process and the character of the satellite.
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| 8. |
- Magnuson, Martin, 1965-, et al.
(författare)
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Coherent and Incoherent Processes in resonant Photoemission
- 1997
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Ingår i: Advanced Light Source. - California, USA : Ernest Orlando Lawrence Berkeley National Laboratory, University of California Berkeley. ; 65:2, s. 159-167
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Bokkapitel (populärvet., debatt m.m.)
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| 9. |
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| 10. |
- Martensson, N, et al.
(författare)
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Coherent and incoherent processes in resonant photoemission
- 1997
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Ingår i: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING. - 0947-8396. ; 65:2, s. 159-167
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The basis for resonant photoemission is discussed in connection with data for a physisorption system, Ar/Pt(111) and a 3d transition metal, Ni(100). For Ar/Pt(111) the quasi-localized character of the intermediate state leads to two types of features in t
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