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- Boukhvalov, D. W., et al.
(författare)
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Electronic structure of a Mn-12 molecular magnet : Theory and experiment
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:1, s. 014419-
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Tidskriftsartikel (refereegranskat)abstract
- We used site-selective and element-specific resonant inelastic x-ray scattering (RIXS) to study the electronic structure and the electron interaction effects in the molecular magnet [Mn12O12(CH3COO)(16)(H2O)(4)]center dot 2CH(3)COOH center dot 4H(2)O, and compared the experimental data with the results of local spin density approximation +U electron structure calculations which include the on-site Coulomb interactions. We found a good agreement between theory and experiment for the Coulomb repulsion parameter U = 4 eV. In particular, the p-d band separation of 1.8 eV has been found from the RIXS spectra, which is in accordance with the calculations. Similarly, the positions of the peaks in the XPS spectra agree with the calculated densities of p and d states. Using the results of the electronic structure calculations, we determined the intramolecular exchange parameters, and used them for diagonalization of the Mn-12 spin Hamiltonian. The calculated exchanges gave the correct ground state with the total spin S = 10.
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- Boukhvalov D. W., Kurmaev E. Z. , Moewes A. , Zatsepin D. A., Cherkashenko V. M., Nemnonov S. N., Finkelstein L. D. , Yarmoshenko Yu. M., Neumann M., Dobrovitski V. V. , Katsnelson M. I. , Lichtenstein A. I. , Harmon B. N. , Kögerler P.
(författare)
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Electronic structure of magnetic molecules V15: LSDA+U calculations, X-ray emission and photoelectron spectra
- 2003
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Ingår i: Physical Review B. ; 67, s. 134408-
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Tidskriftsartikel (refereegranskat)
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- Galakhov, V. R., et al.
(författare)
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Electronic structure and x-ray spectra of defective oxides LixCoO2
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:4, s. 045120-
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Tidskriftsartikel (refereegranskat)abstract
- X-ray absorption, resonant x-ray emission, and x-ray photoelectron spectra of the valence band and core levels have been measured for LixCoO2 (0.6 <= x <= 1.0). Resonant O K alpha x-ray emission spectra of LiCoO2 showed localized excitonic states due to a dd transition between unoccupied and occupied Co 3d states. On the basis of measurements of Co 3s x-ray photoelectron and Co 2p and O 1s x-ray absorption spectra it was established that in defective cobaltites the electronic holes are localized mainly in O 2p states. Evidence of phase separation in LixCoO2 has been found.
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- Kurmaev, E. Z., et al.
(författare)
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Spectroscopic observation of polaron-lattice band structure in the conducting polymer polyaniline
- 2001
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 13:17, s. 3907-3912
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of soft x-ray emission measurements for undoped and protonated polyemeraldine. We show that the polaron-lattice band structure fully accounts for the observed x-ray transitions. A finite spectral intensity of C Kα and N Kα XES is observed at the Fermi level for protonated polyemeraldine, supporting the applicability of the polaronic-metal model for highly conducting polymers.
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- Magnuson, Martin, 1965-, et al.
(författare)
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Magnetic circular dichroism in X-ray fluorescence of Heuseler alloys at threshold excitation
- 2001
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Ingår i: Solid State Communications. - 0038-1098 .- 1879-2766. ; 117:2, s. 79-82
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Tidskriftsartikel (refereegranskat)abstract
- The results of fluorescence measurements of magnetic circular dichroism (MCD) in Mn L2,3 X-ray emission and absorption for Heusler alloys NiMnSb and Co2MnSb are presented. Very intense resonance Mn L3 emission is found at the Mn 2p3/2 threshold and attributed to a peculiarity of the threshold excitation in materials with a half-metallic character of the electronic structure. The excitation energy dependence of Mn L2,3 X-ray emission spectra (XES) was measured at beamline ID12B at the European Synchrotron Radiation Facility (ESRF, Grenoble) using 83% circularly polarized X-rays. A very large MCD effect found in XES is attributed to strong exchange splitting of spin-up and spin-down Mn 3d states. The anomalously high ratio of L2 emission intensity to L3 emission intensity is found.
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