| 1. |
- Rohringer, N., et al.
(författare)
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Stimulated X-Ray Raman Scattering with Free-Electron Laser Sources
- 2016
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Ingår i: X-Ray Lasers 2014. - Cham : Springer. - 0930-8989. - 9783319195216 - 9783319195209 ; , s. 201-207
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Bokkapitel (refereegranskat)abstract
- Stimulated electronic x-ray Raman scattering is the building block for several proposed x-ray pump probe techniques, that would allow the study of electron dynamics at unprecedented timescales.We present high spectral resolution data on stimulated electronic x-ray Raman scattering in a gas sample of neon using a self-amplified spontaneous emission x-ray free-electron laser. Despite the limited spectral coherence and broad bandwidth of these sources, high-resolution spectra can be obtained by statistical methods, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and the results of a recent experiment in CO are discussed.
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| 2. |
- Agui, A., et al.
(författare)
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Direct observation of interface effects of thin AlAs(100) layers buried in GaAs
- 2000
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 166:1-4, s. 309-312
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Tidskriftsartikel (refereegranskat)abstract
- A study of the electronic structure of ultrathin AlAs layers buried in GaAs(100) and their interfaces is presented. Al L2,3 soft-X-ray-emission (SXE) spectra from the AlAs layers were measured. The spectra show distinct thickness-dependent features, which are reproduced using ab initio calculations.
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| 3. |
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| 4. |
- Kashtanov, Stepan, et al.
(författare)
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Local structures of liquid water studied by x-ray emission spectroscopy
- 2004
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:2
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Tidskriftsartikel (refereegranskat)abstract
- The O Kalpha x-ray emission spectra of water clusters with different sizes and conformations embedded in a continuum medium are simulated. The calculations have successfully explained the experimental spectra of water in both gas and liquid phases. It is shown that the x-ray emission spectra are very sensitive to the local hydrogen bonding structures. Strong electron sharing between different water molecules is observed and its possible connection to the covalency of hydrogen bonding is discussed. The experimentally observed strong excitation energy dependence of the spectra has been interpreted in terms of the polarization and angular dependence for the gas phase, and in terms of variations of local hydrogen bonding structures for the liquid phase.
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| 5. |
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| 6. |
- Mankefors, S., et al.
(författare)
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Theoretical investigation of the thickness dependence of soft-x-ray emission from thin AlAs(100) layers buried in GaAs
- 2000
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Ingår i: Physical Review B Condensed Matter. - : American Physical Society. - 0163-1829 .- 1095-3795. ; 61:8, s. 5540-5545
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Tidskriftsartikel (refereegranskat)abstract
- Ultrathin AlAs(100) layers of 1-, 2-, and 5-ML thickness buried in GaAs are investigated by ab initio calculations. Unique experimental soft-x-ray emission spectra are explained in terms of interface effects and changes with layer thickness are found in the density of states. Only the central layer in the 5-ML geometry is bulklike. A valence-band offset of 0.53 eV is also found for this structure, while no offset exists in the 1- and 2-ML cases. Very good agreement is achieved between theory and experiment.
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| 7. |
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| 8. |
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| 9. |
- Skytt, P, et al.
(författare)
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Quenching of symmetry breaking in resonant inelastic X-ray scattering by detuned excitation
- 1996
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Ingår i: Physical Review Letters. - 0031-9007. ; 77:25, s. 5035-5038
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Tidskriftsartikel (refereegranskat)abstract
- Observations made in oxygen K emission of CO2 show that the symmetry selective character of resonant x-ray emission is excitation energy dependent. Electronically dipole forbidden O K emission lines are observed for excitation at the O 1s --> pi* resonance, and they are gradually reduced upon detuning the excitation energy below threshold. The occurrence of forbidden transitions is explained in terms of dynamical symmetry breaking due to vibronic coupling, and the observation of quenching of the symmetry breaking upon detuning as due to an effective quenching of this vibronic coupling. Scattering theory applied to a few-level system is shown to account for the energy dependence of the symmetry selection in the limit of narrow bandpass photon excitation.
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| 10. |
- Såthe, C., et al.
(författare)
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Resonant LII;III x-ray raman scattering from HCl
- 2006
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Ingår i: Physical Review A. - 1050-2947 .- 1094-1622. ; 74:6, s. 062512-
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the spectral features of Cl LII,III resonant x-ray Raman scattering of HCl molecules in gas phase both experimentally and theoretically. The theory, formulated in the intermediate-coupling scheme, takes into account the spin-orbital and molecular-field splittings in the Cl 2p shells, as well as the Coulomb interaction of the core hole with unoccupied molecular orbitals. Experiment and theory display nondispersive dissociative peaks formed by decay transitions in both molecular and dissociative regions. The molecular and atomic peaks collapse in a single narrow resonance because the dissociative potentials of core-excited and final states are parallel to each other along the whole pathway of the nuclear wave packet.
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