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  • 51. Miao, Q.
    et al.
    Liu, J. C.
    Agren, H.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Gel'mukhanov, F.
    Dissociative X-ray Lasing2012Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, nr 23, s. 233905-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    X-ray lasing is predicted to ensue when molecules are pumped into dissociative core-excited states by a free-electron-laser pulse. The lasing is due to the population inversion created in the neutral dissociation product, and the process features self-trapping of the x-ray pulse at the gain ridge. Simulations performed for the HCl molecule pumped at the 2p(1/2) -> 6 sigma resonance demonstrate that the scheme can be used to create ultrashort coherent x-ray pulses.

  • 52.
    Modin, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Yun, Y.
    Suzuki, M. -T
    Vegelius, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Werme, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Nordgren, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Oppeneer, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Butorin, Sergei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Indication of single-crystal PuO2 oxidation from O 1s x-ray absorption spectra2011Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, nr 7, s. 075113-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electronic structure of single-crystal PuO2 is studied using O 1s x-ray absorption (XA) and x-ray emission. Interpretation of the experimental data is supported by extensive first-principles calculations on the basis of the density functional theory + U approach. The measured XA spectra show a significant difference in intensity for the first two peaks between different spots or areas on the single crystal. Our theoretical simulations show that the first peak, at similar to 531 eV, can be attributed to O 2p-Pu 5f hybridization, while the second peak, at similar to 533.4 eV, is due to hybridization of O 2p with Pu d states. The reasons for the observed differences in the O 1s XA spectra are explored by calculating a number of defect structures PuO2+x as well as by simulating the existence of Pu(V) sites. Our results indicate the presence of oxidation states higher than Pu(IV) in some areas of the single crystal. The findings also suggest that plutonium oxide with a Pu fraction in an oxidation state higher than Pu(IV) consists of inequivalent Pu sites with (PuO2)-O-(IV) and (PuO2)-O-(V) rather than representing a system where the Pu oxidation state is constantly fluctuating between Pu(IV) and Pu(V).

  • 53. Mosquera, Adolfo
    et al.
    Horwat, David
    Vazquez, Luis
    Gutierrez, Alejandro
    Erko, Alexei
    Anders, Andre
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Endrino, Jose L.
    Thermal decomposition and fractal properties of sputter-deposited platinum oxide thin films2012Ingår i: Journal of Materials Research, ISSN 0884-2914, E-ISSN 2044-5326, Vol. 27, nr 5, s. 829-836Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Porous platinum thin films were prepared by thermal decomposition at temperatures from 25 to 675 degrees C of platinum oxide films deposited by a pulsed reactive sputtering technique. The samples' chemistry and structure were investigated by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and x-ray absorption near edge structure (XANES), showing that the decomposition of the oxide begins as low as 400 degrees C and follows a sigmoidal trend with increasing annealing temperature. In the XRD spectra, only an amorphous-like signature was observed for temperatures below 575 degrees C, while Pt 4f XPS showed that the deposited oxide was a mixture of PtO2 and PtO. Pt-L-3 edge XANES and Pt 4f XPS spectra showed that the Pt concentration and electronic structure are predominant for temperatures equal to or above 575 degrees C. The morphologies of the films were investigated by the area-perimeter method from atomic force microscopy and scanning electron microscopy (SEM) images, indicating that the surfaces exhibit a combination of Euclidian and fractal characteristics. Moreover, the thermal evolution of these characteristics indicates the agglomeration of the grains in the film as observed by SEM.

  • 54. Nagaya, K.
    et al.
    Sugishima, A.
    Iwayama, H.
    Murakami, H.
    Yao, M.
    Fukuzawa, H.
    Liu, X. -J
    Motomura, K.
    Ueda, K.
    Saito, N.
    Rudenko, A.
    Kurka, M.
    Kuhne, K. -U
    Ullrich, J.
    Foucar, L.
    Czasch, A.
    Dorner, R.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Nagasono, M.
    Higashiya, A.
    Togashi, T.
    Yabashi, M.
    Ishikawa, T.
    Kimura, H.
    Ohashi, H.
    Formation of the energetic doubly charged ne ion by irradiation of large neon clusters using intense EUV-FEL pulses at 52 nm2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    The interaction of clusters with intense EUV-FEL pulses was investigated using the SPring-8 Compact SASE Source (SCSS) test facility in Japan. Neon clusters of mean sizes <N> = 1000 and 4000 were irradiated by intense FEL pulses at 52 nm and emitted ions were detected by a momentum imaging spectrometer. The production of energetic doubly charged ions was not found for Ne 1000, but it was observed for Ne 4000 clusters, which suggests that an inhomogeneous charge distribution is generated for the larger clusters.

  • 55. Niskanen, J.
    et al.
    Andersson, E.
    Eland, John H. D.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Linusson, P.
    Hedin, Lage
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Karlsson, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Vahtras, O.
    Symmetry breaking in core-valence double photoionization of SO22012Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 85, nr 2, s. 023408-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Core-valence double photoionization electron spectra of the SO2 molecule involving the S 2p and O 1s inner shells have been measured using a time-of-flight multiparticle coincidence technique. The experimental spectra are compared with quantum-chemical calculations based on density functional theory by which several core-valence dicationic states are identified. Assignments conform with a picture where the formation of a O 1s-valence dicationic state is associated with a physical, "pseudo-Jahn-Teller," symmetry breaking and core-hole localization. It is shown that while density functional theory gives very good transition energies in the symmetry-broken case, it gives a poor representation in the symmetry-restricted case, and an incomplete account of the Hartree-Fock localization energy.

  • 56. Niskanen, J.
    et al.
    Carravetta, V.
    Vahtras, O.
    Ågren, H.
    Aksela, H.
    Andersson, Egil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Hedin, Lage
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Linusson, P.
    Eland, John H. D.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Karlsson, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Experimental and theoretical study of core-valence double photoionization of OCS2010Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, nr 4, s. 043436-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    O 1s, C 1s, and S 2p core-valence double ionization electron spectra of the OCS molecule have been obtained experimentally by a time-of-flight photoelectron-photoelectron coincidence spectroscopy technique. In order to analyze and assign the spectral features observed, we present a protocol for computing core-valence ionization energies of such systems. The protocol is based on a restricted active space multiconfigurational self-consistent field (MCSCF) methodology with a freeze-relax procedure to guarantee a correct core-valence state root index without variational collapse. Corrections for extended dynamical correlation and core-core correlation, respectively, are made by multiconfigurational perturbation theory and by uncontracted basis set Moller-Plesset theory. Envisioning applications to larger molecules, a spin-restricted open-shell density functional method is also applied for the lowest core-valence energies. Furthermore, cross sections through a scheme for computing multiatom Auger transitions generating core-valence holes are presented. We find that the procedure outlined is capable of deriving the energy onset of core-valence ionization within a fraction of an eV and that assignments can be made of the most salient spectral features.

  • 57. Palm, Fredrik
    et al.
    El-Daoushy, Farid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Svensson, Jan-Erik
    Development of subfossil Daphnia and Chaoborus assemblages in relation to progressive acidification and fish community alterations in SW Sweden2012Ingår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 684, nr 1, s. 83-95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dated sediment cores from acidified and fishless Lake Gaffeln and Lake Harsvatten, SW Sweden, were analyzed for Daphnia ephippia and Chaoborus mandibles to test whether acidification history and fish extirpations could be reconstructed in a paleo-study using these easily identifiable animal remains. According to monitoring data fish were lost in both lakes from the 1950s to the 1970s. Progressive acidification prior to monitoring was confirmed by a gradual decrease and eventual loss of Daphnia ephippia in both study lakes during the first half of the twentieth century. In Lake Gaffeln mandibles of C. obscuripes appeared immediately after fish loss in 1973, and the regular presence of this species confirmed the succeeding fishless state of this lake. In Lake Harsvatten sediments C. obscuripes appeared only recently, i.e. three decades after fish extirpation, showing that the absence of C. obscuripes mandibles is not a trustworthy indicator of fish presence. Hence, the appearance of C. obscuripes was not temporally related to fish loss but confirmed the present fishless condition. Known historical presence of cyprinid fish in Lake Gaffeln was confirmed by a significantly higher proportion of fragmented mandibles of C. flavicans compared to the historically cyprinid-free Lake Harsvatten. In addition, both lake profiles displayed zero-proportions of fragmented mandibles during fishless periods. We conclude that acidification history and fish extirpations can be inferred by integrated studies on subfossil Daphnia ephippia and Chaoborus mandibles. However, during extreme ultra-oligotrophic conditions in acidified clear-water lakes subfossil Chaoborus mandibles may be too scarce to infer fish absence/presence.

  • 58.
    Palm, Fredrik
    et al.
    Department of Zoology, University of Gothenburg, Sweden.
    El-Daoushy, Farid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Svensson, Jan-Erik
    Medins Biologi AB, Företagsvägen 2, S-435 33 Mölnlycke.
    Fragmented subfossil Chaoborus mandibles reveal periods of cyprinid presence in lake histories2011Ingår i: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 45, nr 1, s. 101-113Artikel i tidskrift (Refereegranskat)
  • 59. Palm, Fredrik
    et al.
    El-Daoushy, Farid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Svensson, Jan-Erik
    Fragmented subfossil Chaoborus mandibles reveal periods of cyprinid presence in lake histories2011Ingår i: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 45, nr 1, s. 101-113Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cyprinid fish have pharyngeal teeth that mash ingested food. Here we show that roach (Rutilus rutilus L.), a common cyprinid in Swedish boreal lakes, often break the mandibles of ingested Chaoborus larvae into smaller fragments. The presence/absence of roach in historic fish communities could therefore possibly be determined from the proportion of fragmented Chaoborus mandibles in lake sediments, which we assessed using the following three approaches. (1) Roach that were fed Chaoborus larvae in laboratory aquaria evacuated a significantly higher fraction of fragmented prey mandibles than perch (Perca fluviatilis L.). (2) Surface sediments from lakes in an acidified region in southwestern Sweden showed significantly higher proportions of fragmented mandibles for lakes containing roach compared to lakes devoid of cyprinid fish. (3) A paleo-study in Lake Lysevatten, into which roach were introduced in the 1880s and were extirpated in the 1960s, showed significantly higher proportions of fragmented mandibles in sediment layers from the roach period. We conclude that mandible fragmentation was related to roach presence, and propose that the proportion of fragmented Chaoborus mandibles in lake sediments may provide important information when historical cyprinid alterations are of interest, as in paleo-studies on acidification, eutrophication, or fish introductions.

  • 60.
    Pietzsch, A.
    et al.
    MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden.
    Sun, Y. -P
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Rinkevicius, Z.
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Karlsson, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Kvantkemi.
    Schmitt, T.
    Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Strocov, V. N.
    Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Kennedy, B.
    MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden.
    Schlappa, J.
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G-I2, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
    Foehlisch, A.
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G-I2, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Gel'mukhanov, F.
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Spatial Quantum Beats in Vibrational Resonant Inelastic Soft X-Ray Scattering at Dissociating States in Oxygen2011Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, nr 15, s. 153004-1-153004-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1 sigma(g) -> 3 sigma(u) resonance in gas-phase O-2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.

  • 61.
    Pietzsch, Annette
    et al.
    MAXlab, Lund University.
    Nisar, Jawad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Jamstorp, Erik
    Gråsjö, Johan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Kennedy, Brian
    Hennies, Franz
    Arhammar, Cecilia
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Kaolinite: defect states define material properties-a soft x-ray and first principles study of the band gap2015Ingår i: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 202, s. 11-15Artikel i tidskrift (Refereegranskat)
  • 62.
    Plogmaker, Stefan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Linusson, Per
    Eland, John H D
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Baker, Neville
    Johansson, Erik M J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Siegbahn, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region2012Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, nr 1, s. 013115-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of ∼8 to ∼120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

  • 63. Rothe, J.
    et al.
    Butorin, Sergei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Dardenne, K.
    Denecke, M. A.
    Kienzler, B.
    Loeble, M.
    Metz, V.
    Seibert, A.
    Steppert, M.
    Vitova, T.
    Walther, C.
    Geckeis, H.
    The INE-Beamline for actinide science at ANKA2012Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, nr 4, s. 043105-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since its inauguration in 2005, the INE-Beamline for actinide research at the synchrotron source ANKA (KIT North Campus) provides dedicated instrumentation for x-ray spectroscopic characterization of actinide samples and other radioactive materials. R&D work at the beamline focuses on various aspects of nuclear waste disposal within INE's mission to provide the scientific basis for assessing long-term safety of a final nuclear waste repository. The INE-Beamline is accessible for the actinide and radiochemistry community through the ANKA proposal system and the European Union Integrated Infrastructure Initiative ACTINET-I3. Experiments with activities up to 1 x 10(+6) times the European exemption limit are feasible within a safe but flexible containment concept. Measurements with monochromatic radiation are performed at photon energies varying between similar to 2.1 keV (P K-edge) and similar to 25 keV (Pd K-edge), including the lanthanide L-edges and the actinide M-and L3-edges up to Cf. The close proximity of the INE-Beamline to INE controlled area labs offers infrastructure unique in Europe for the spectroscopic and microscopic characterization of actinide samples. The modular beamline design enables sufficient flexibility to adapt sample environments and detection systems to many scientific questions. The well-established bulk techniques x-ray absorption fine structure (XAFS) spectroscopy in transmission and fluorescence mode have been augmented by advanced methods using a microfocused beam, including (confocal) XAFS/x-ray fluorescence detection and a combination of (micro-)XAFS and (micro-)x-ray diffraction. Additional instrumentation for high energy-resolution x-ray emission spectroscopy has been successfully developed and tested.

  • 64.
    Rubensson, Jan-Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Moise, A.
    Mihelic, A.
    Bucar, K.
    Zitnik, M.
    Richter, R.
    Experimental confirmation of photon-induced spin-flip transitions in helium via triplet metastable yield spectra2010Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 81, nr 6, s. 062510-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Doubly excited states below the N = 2 ionization threshold are populated by exciting helium atoms in a supersonic beam with monochromatized synchrotron radiation. The fluorescence decay of these states triggers a radiative cascade back to the ground state with large probability to populate long lived singlet and triplet helium metastable states. The yield of metastables is measured using a multichannel plate detector after the beam has passed a singlet-quenching discharge lamp. The variation of the yield observed with the lamp switched on or off is related to the triplet-singlet mixing of the doubly excited states.

  • 65.
    Rubensson, Jan-Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Pietzsch, Annette
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Vibrationally resolved resonant inelastic soft X-ray scattering spectra of free molecules2012Ingår i: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 185, nr 8-9, s. 294-300Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The brilliance of modern synchrotron radiation sources and capabilities of new instrumentation facilitate molecular resonant inelastic soft X-ray scattering with high spectral quality. Especially, energy resolution of vibrational fine structure allows for a detailed analysis, providing information about the dynamic coupling between nuclear and electronic degrees of freedom. After a brief historical account and a short qualitative comparison between the radiative and non-radiative decay channels we review the recent results for the oxygen molecule. Nuclear wavepacket dynamics in bound and unbound states is studied, and in the latter case spatial quantum beats are observed as the dissociation proceeds via two different electronic states. A new internal spin-coupling conservation rule is established, whereas a commonly accepted selection rule based on orbital symmetry is violated.

  • 66. Saleacuten, P.
    et al.
    van der Meulen, P.
    Thomas, R. D.
    Schmidt, H. T.
    Larsson, M.
    Feifel, R.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Piancastelli, M. N.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Fang, L.
    Osipov, T.
    Murphy, B.
    Juranic, P.
    Berrah, N.
    Kukk, E.
    Ueda, K.
    Richter, R.
    Prince, K. C.
    Bozek, J. D.
    Bostedt, C.
    Wada, S.
    Tashiro, M.
    Ehara, M.
    Tarantelli, F.
    X-ray FEL-induced Double Core-Hole Formation in Polyatomic Molecules2012Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, nr 2, s. 022083-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use extremely intense, ultrashort soft X-Ray pulses generated by the LCLS X-Ray Free Electron Laser to investigate the production of molecular double core-hole states by sequential two-photon X-Ray absorption. The effect of critical LCLS parameters such as the number of photons per pulse, the pulse duration, and the focal spot size on the photoelectron and Auger spectra is modeled in detail and the results of these simulations are used as an aid in the interpretation of the experimental spectra obtained. The emphasis is on double core-hole formation in small polyatomic molecules such as CO2.

  • 67. Salen, P.
    et al.
    van der Meulen, P.
    Schmidt, H. T.
    Thomas, R. D.
    Larsson, M.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Piancastelli, Maria Novella
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Fang, L.
    Murphy, B.
    Osipov, T.
    Berrah, N.
    Kukk, E.
    Ueda, K.
    Bozek, J. D.
    Bostedt, C.
    Wada, S.
    Richter, R.
    Feyer, V.
    Prince, K. C.
    Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-Ray Free-Electron Laser2012Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 108, nr 15, s. 153003-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have performed x-ray two-photon photoelectron spectroscopy using the Linac Coherent Light Source x-ray free-electron laser in order to study double core-hole (DCH) states of CO2, N2O, and N2. The experiment verifies the theory behind the chemical sensitivity of two-site DCH states by comparing a set of small molecules with respect to the energy shift of the two-site DCH state and by extracting the relevant parameters from this shift.

  • 68.
    Schiessling, Joachim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Grigoriev, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Stener, Mauro
    Kjeldgaard, Lisbeth
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Balasubramanian, Thiagarajan
    Decleva, Piero
    Ahuja, Rajeev
    Nordgren, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Brühwiler, Paul A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    The Role of Charge-Charge Correlations and Covalent Bonding in the Electronic Structure of Adsorbed C-60: C-60/A12010Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, nr 43, s. 18686-18692Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aromatic molecules are central components of model systems for molecular electronics, with C-60 one of the most studied. Upon adsorption on (metallic) substrates a splitting of the frontier orbitals is commonly observed, with a strong dependence on substrate material, but little dependence on substrate structure. We report the detailed photoelectron angle dependence of C-60/A1(110) over a wide range of energy, finding a strong remnant molecular character. In particular, certain HOMO-derived suborbitals couple strongly, and others weakly, with the metal, which results in final state charging for those weakly coupled. C Is data correlate well with the assignments made on this basis, as does the comparison of ground state partial densities-of-states (PDOS) to photoelectron spectra. Detailed analysis of the PDOS supports a rough division into surface-near and surface-far components, in agreement with the molecular picture. The component spectral widths are attributed to intramolecular vibrational coupling, which is suggested to aid in the electronic decoupling of certain suborbitals from the substrate, facilitating the observed final state charging.

  • 69. Sheinerman, S.
    et al.
    Linusson, P.
    Eland, John H. D.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Hedin, Lage
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Andersson, E.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Karlsson, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Influence of double Auger decay on low-energy 3d photoelectrons of krypton2012Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, nr 2, s. 022515-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Effects of postcollision interaction (PCI) observable in low-energy 3d photoelectron spectra of Kr, which are associated with double Auger decay of the created inner-shell vacancy, are investigated by a combined experimental and theoretical approach. Measurements are based on an efficient multielectron coincidence method. Calculations have been carried out in the framework of a semiclassical approach. Our investigation reveals strong PCI distortion of the photoelectron line shapes, which depends on the kinematics of the process and the characteristics of the double Auger decay.

  • 70.
    Soroka, Inna L.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Vegelius, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Korelis, Panagiotis T.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Fallberg, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Butorin, Sergei M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Hjörvarsson, Björgvin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap.
    Structural stability and oxidation resistance of amorphous Zr-Al alloys2010Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 401, nr 1-3, s. 38-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigated the structural stability and oxidation resistance of Zr-Al films upon annealing in air. The concentration of Zr was varied from 0 to 100 at.%, with a step of 10 at.%. The films were fabricated using ultra-high vacuum based magnetron sputtering. The as-deposited films with Zr content from 17.3 at.% to 70.7 at.% were found to be X-ray amorphous at room temperature. When exposed to air a thin oxide layer, typically less than 6 nm, is formed. The thickness of the oxide layers increases when the samples are annealed in air and most of these are found to be fully oxidized at 700 degrees C with the formation of crystalline and amorphous oxides on the top of crystalline and amorphous metal films, respectively. The amorphous oxide layers are found to be dense, with well defined thicknesses. An experimental non-equilibrium phase diagram is provided, covering the whole concentration range of the Zr-Al system. (C) 2010 Elsevier B.V. All rights reserved.

  • 71. Sugishima, A.
    et al.
    Iwayama, H.
    Yase, S.
    Murakami, H.
    Nagaya, K.
    Yao, M.
    Fukuzawa, H.
    Liu, X. -J
    Motomura, K.
    Ueda, K.
    Saito, N.
    Foucar, L.
    Rudenko, A.
    Kurka, M.
    Kuehnel, K. -U
    Ullrich, J.
    Czasch, A.
    Doerner, R.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Nagasono, M.
    Higashiya, A.
    Yabashi, M.
    Ishikawa, T.
    Togashi, T.
    Kimura, H.
    Ohashi, H.
    Charge and energy transfer in argon-core-neon-shell clusters irradiated by free-electron-laser pulses at 62 nm2012Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, nr 3, s. 033203-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The multiple ionization of Ar-core-Ne-shell clusters in intense extreme-ultraviolet laser pulses (lambda similar to 62 nm) from the free-electron laser in Japan was investigated utilizing a momentum imaging technique. The Ar composition dependence of the kinetic energies and the yields of the fragment ions give evidence for charge transfer from the Ar core to the Ne shell. We have extended the uniformly charged sphere model originally applied to pristine clusters [Islam et al., Phys. Rev. A 73, 041201 (R) (2006)] to the core-shell heterogeneous clusters to estimate the amounts of charge and energy transfers.

  • 72. Sun, Y. -P
    et al.
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Pietzsch, A.
    Kennedy, B.
    Schmitt, T.
    Strocov, V. N.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Berglund, M.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Aidas, K.
    Gel'mukhanov, F.
    Odelius, M.
    Foehlisch, A.
    Intramolecular soft modes and intermolecular interactions in liquid acetone2011Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, nr 13, s. 132202-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Resonant inelastic x-ray scattering spectra excited at the O1s(-1)pi* resonance of liquid acetone are presented. Scattering to the electronic ground state shows a resolved vibrational progression where the dominant contribution is due to the C-O stretching mode, thus demonstrating a unique sensitivity of the method to the local potential energy surface in complex molecular systems. For scattering to electronically excited states, soft vibrational modes and, to a smaller extent, intermolecular interactions give a broadening, which blurs the vibrational fine structure. It is predicted that environmental broadening is dominant in aqueous acetone.

  • 73. Sun, Y-P
    et al.
    Pietzsch, A.
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Rinkevicius, Z.
    Karlsson, Hans O.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Kvantkemi.
    Schmitt, T.
    Strocov, V. N.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Kennedy, B.
    Schlappa, J.
    Föhlisch, A.
    Gel'mukhanov, F.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Internal symmetry and selection rules in resonant inelastic soft x-ray scattering2011Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 44, nr 16, s. 161002-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Resonant inelastic soft x-ray scattering spectra excited at the dissociative 1 sigma(g) -> 3 sigma(u) resonance in gas-phase O(2) are presented and discussed in terms of state-of-the-art molecular theory. A new selection rule due to internal spin coupling is established, facilitating a deep analysis of the valence excited final states. Furthermore, it is found that a commonly accepted symmetry selection rule due to orbital parity breaks down, as the core hole and excited electron swap parity, thereby opening the symmetry forbidden 3 sigma(g) decay channel.

  • 74.
    Såthe, Conny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Applications of Soft X-Ray Spectroscopy2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Soft X-ray emission spectroscopy is an old experimental technique that has seen a strong revival since the advent of new high brilliance soft X-ray sources in the shape of synchrotrons.  This thesis covers a range of applications where soft x-ray techniques have been applied. I have looked at fluorescence yield from doubly excited helium in field free conditions as well as in the presence of weak electric and magnetic fields. Using soft X-ray emission spectroscopy (SXES) I have explored scattering mechanisms in molecular systems. Quenching of symmetry breaking transitions by detuning of the excitation energy was observed in CO2. Bond-length dependence was seen for symmetry breaking transitions in a series of hydrocarbons. Dissociation dynamics was explored in OCS and HCl. I have also applied SXES to liquid water exploring the properties of hydrogen bonding.  Buried layers of AlAs under 100 Å GaAs(100) was studied and thickness dependence and interface effects observed. The technique was also used to study the electronic structure of yttrium and vanadium hydrides. dd-excitations and accompanying spin flip excitations was observed in Cu M resonant x-ray Raman emission from Sr2CuO2Cl2.

    Delarbeten
    1. Influence of the Radiative Decay on the Cross Section for Double Excitations in Helium
    Öppna denna publikation i ny flik eller fönster >>Influence of the Radiative Decay on the Cross Section for Double Excitations in Helium
    Visa övriga...
    1999 (Engelska)Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 83, nr 5, s. 947-950Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The fluorescence yield spectrum of the double excitations in helium has been measured. All three Rydberg series converging to the N = 2 threshold are resolved, and the intensity of the individual lines is determined. The intensity variation through each series indicates that the radiative decay channel cannot be neglected when discussing the double excitations in helium. This calls for a revision of the interpretation of the absorption spectrum, and sets the limit for using the ion yield method to monitor the absorption probability.

    Nyckelord
    excited-states, high-resolution, threshold, lifetime, He+
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-66856 (URN)10.1103/PhysRevLett.83.947 (DOI)
    Tillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2017-11-28Bibliografiskt granskad
    2. Radiative and Relativistic Effects in the Decay of Highly Excited States in Helium
    Öppna denna publikation i ny flik eller fönster >>Radiative and Relativistic Effects in the Decay of Highly Excited States in Helium
    Visa övriga...
    2000 (Engelska)Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 85, nr 6, s. 1202-1205Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A recent experimental study [J.-E. Rubensson et al., Phys. Rev. Lett. 83, 947 (1999)] measured a significant fluorescence yield of the He( 2lnl) photoexcited resonances, showing major qualitative differences from nonrelativistic predictions. We present a further theoretical study of these states, and perform R-matrix multichannel quantum defect theory calculations to extract fluorescence and ionization cross sections. These theoretical results are in excellent agreement with newer, higher-resolution measurements. Radiative and spin-orbit effects are quantified and shown to play an important role in the overall characterization of highly excited states.

    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-94516 (URN)10.1103/PhysRevLett.85.1202 (DOI)
    Tillgänglig från: 2006-05-05 Skapad: 2006-05-05 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    3. Double Excitations of Helium in Weak Static Electric Fields
    Öppna denna publikation i ny flik eller fönster >>Double Excitations of Helium in Weak Static Electric Fields
    Visa övriga...
    2006 Ingår i: Physical Review Letters, ISSN 0031-9007, Vol. 96, s. 043002-Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-95805 (URN)
    Tillgänglig från: 2007-04-24 Skapad: 2007-04-24 Senast uppdaterad: 2016-04-26Bibliografiskt granskad
    4. Magnetic-field induced enhancement in the fluorescence yield spectrum of doubly excited states in helium
    Öppna denna publikation i ny flik eller fönster >>Magnetic-field induced enhancement in the fluorescence yield spectrum of doubly excited states in helium
    Visa övriga...
    2006 (Engelska)Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 97, nr 25, s. 253002-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    An influence of static magnetic fields on the fluorescence yield spectrum of He in the vicinity of the N=2 thresholds has been observed. The experimental results are in excellent agreement with predictions based on multichannel quantum defect theory, and it is demonstrated that the Rydberg electron ℓ mixing due to the diamagnetic interaction is essential for the description of the observed fluorescence yield intensity enhancement.

    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-95806 (URN)10.1103/PhysRevLett.97.253002 (DOI)000243414600018 ()
    Tillgänglig från: 2007-04-24 Skapad: 2007-04-24 Senast uppdaterad: 2017-12-14
    5. Quenching of symmetry breaking in resonant inelastic X-ray scattering by detuned excitation
    Öppna denna publikation i ny flik eller fönster >>Quenching of symmetry breaking in resonant inelastic X-ray scattering by detuned excitation
    Visa övriga...
    1996 (Engelska)Ingår i: PHYSICAL REVIEW LETTERS, ISSN 0031-9007, Vol. 77, nr 25, s. 5035-5038Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    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* resonanc

    Ort, förlag, år, upplaga, sidor
    AMER INST PHYSICS, 1996
    Nyckelord
    BAND-STRUCTURE; EMISSION; FLUORESCENCE; LOCALIZATION; CK
    Identifikatorer
    urn:nbn:se:uu:diva-74059 (URN)
    Anmärkning
    Addresses: Skytt P, UNIV UPPSALA, DEPT PHYS, BOX 530, S-75121 UPPSALA, SWEDEN. UNIV NEVADA, DEPT CHEM, LAS VEGAS, NV 89154. LINKOPING UNIV, INST PHYS & MEASUREMENT TECHNOL, S-58183 LINKOPING, SWEDEN.Tillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2011-11-04
    6. Bond-length-dependent core hole localization observed in simple hydrocarbons
    Öppna denna publikation i ny flik eller fönster >>Bond-length-dependent core hole localization observed in simple hydrocarbons
    Visa övriga...
    1999 (Engelska)Ingår i: PHYSICAL REVIEW LETTERS, ISSN 0031-9007, Vol. 83, nr 7, s. 1315-1318Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    Soft x-ray-emission spectroscopy is applied to measure the amount of dynamic symmetry breaking in core-excited acetylene, ethylene, and ethane. Large variations are observed between the molecules and are rationalized in terms of the different C-C bond len

    Ort, förlag, år, upplaga, sidor
    AMERICAN PHYSICAL SOC, 1999
    Nyckelord
    X-RAY-EMISSION; K-SHELL EXCITATION; PHOTOELECTRON-SPECTRA; SYMMETRY-BREAKING; HIGH-RESOLUTION; VIBRATIONAL STRUCTURE; SPECTROSCOPY; SCATTERING; IONIZATION; ETHENE
    Identifikatorer
    urn:nbn:se:uu:diva-66755 (URN)
    Anmärkning
    Addresses: Gunnelin K, Univ Uppsala, Dept Phys, Box 530, S-75121 Uppsala, Sweden. Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Mid Sweden Univ, Dept Phys & Math, S-85170 Sundsvall, Sweden. Linkoping Univ, Inst Phys & Measurement Technol, S-58183 LinkTillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2011-11-04
    7. Competition between decay and dissociation of core-excited carbonyl sulfide studied by x-ray scattering
    Öppna denna publikation i ny flik eller fönster >>Competition between decay and dissociation of core-excited carbonyl sulfide studied by x-ray scattering
    Visa övriga...
    1999 (Engelska)Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 59, nr 6, s. 4281-4287Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We show evidence of dissociation during resonant inelastic soft x-ray scattering. Carbon and oxygen K-shell and sulfur L-shell resonant and nonresonant x-ray emission spectra were measured using monochromatic synchrotron radiation for excitation and ionization. After sulfur L2,3→π*, σ* excitation, atomic lines are observed in the emission spectra as a consequence of competition between de-excitation and dissociation. In contrast the carbon and oxygen spectra show weaker line-shape variations and no atomic lines. The spectra are compared to results from ab initio calculations. The discussion of the dissociation paths is based on calculated potential energy surfaces and atomic transition energies.

    Nyckelord
    HIGH-RESOLUTION; OCS MOLECULE; ABSORPTION SPECTRA; STATIC EXCHANGE; AUGER-SPECTRA; AB-INITIO; EMISSION; CS2; DYNAMICS; HCL
    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-67148 (URN)10.1103/PhysRevA.59.4281 (DOI)
    Tillgänglig från: 2006-11-08 Skapad: 2006-11-08 Senast uppdaterad: 2019-07-01Bibliografiskt granskad
    8. Resonant L-II,L-III x-ray Raman scattering from HCl
    Öppna denna publikation i ny flik eller fönster >>Resonant L-II,L-III x-ray Raman scattering from HCl
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    2006 (Engelska)Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 74, nr 6, s. 062512-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We have studied the spectral features of Cl L-II,L-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.

    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-146649 (URN)10.1103/PhysRevA.74.062512 (DOI)000243166700063 ()
    Tillgänglig från: 2011-02-21 Skapad: 2011-02-18 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    9. X-Ray Emission Spectroscopy of Hydrogen Bonding and Electronic Structure of Liquid Water
    Öppna denna publikation i ny flik eller fönster >>X-Ray Emission Spectroscopy of Hydrogen Bonding and Electronic Structure of Liquid Water
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    2002 Ingår i: Physical Review Letters, ISSN 0031-9007, Vol. 89, nr 13, s. 137402-Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-92079 (URN)
    Tillgänglig från: 2004-09-17 Skapad: 2004-09-17 Senast uppdaterad: 2011-11-04Bibliografiskt granskad
    10. Local structures of liquid water studied by x-ray emission spectroscopy
    Öppna denna publikation i ny flik eller fönster >>Local structures of liquid water studied by x-ray emission spectroscopy
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    2004 Ingår i: Physical Review B (Condensed Matter and Materials Physics -1(II)), ISSN 1098-0121, Vol. 69, s. 024201-Artikel i tidskrift (Refereegranskat) Published
    Identifikatorer
    urn:nbn:se:uu:diva-92080 (URN)
    Tillgänglig från: 2004-09-17 Skapad: 2004-09-17 Senast uppdaterad: 2011-11-04Bibliografiskt granskad
    11. Direct observation of interface effects of thin AlAs(100) layers buried in GaAs
    Öppna denna publikation i ny flik eller fönster >>Direct observation of interface effects of thin AlAs(100) layers buried in GaAs
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    2000 (Engelska)Ingår i: APPLIED SURFACE SCIENCE, ISSN 0169-4332, Vol. 166, nr 1-4, s. 309-312Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A study of the electronic structure of ultrathin AlAs layers buried in GaAs(100) and their interfaces is presented. Al L-2,L-3 soft-X-ray-emission (SXE) spectra from the AlAs layers were measured. The spectra show distinct thickness-dependent features, wh

    Ort, förlag, år, upplaga, sidor
    ELSEVIER SCIENCE BV, 2000
    Nyckelord
    interface; AlAs; soft X-ray emission; synchrotron radiation; X-RAY EMISSION
    Identifikatorer
    urn:nbn:se:uu:diva-36883 (URN)
    Anmärkning
    Addresses: Agui A, JAERI, SPring 8, Sayo, Hyogo 6795143, Japan. JAERI, SPring 8, Sayo, Hyogo 6795143, Japan. Univ Uppsala, Dept Phys, SE-75121 Uppsala, Sweden. Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden. Hogskolan I Skovde, Dept Nat SciTillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2011-11-04
    12. Theoretical investigation of the thickness dependence of soft-x-ray emission from thin AlAs(100) layers buried in GaAs
    Öppna denna publikation i ny flik eller fönster >>Theoretical investigation of the thickness dependence of soft-x-ray emission from thin AlAs(100) layers buried in GaAs
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    2000 (Engelska)Ingår i: PHYSICAL REVIEW B, ISSN 1098-0121, Vol. 61, nr 8, s. 5540-5545Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Ultrathin AlAs(100) layers of 1-, 2-, and 5-ML thickness buried in GaAs are investigated by nb initio calculations. Unique experimental soft-x-ray emission spectra are explained in terms of interface effects and changes with layer thickness are found in t

    Ort, förlag, år, upplaga, sidor
    AMERICAN PHYSICAL SOC, 2000
    Nyckelord
    NORM-CONSERVING PSEUDOPOTENTIALS; BAND OFFSETS; GAAS/ALAS SUPERLATTICES; ELECTRONIC-STRUCTURE; GROUND-STATE; MODEL; HETEROJUNCTIONS; SURFACES; DENSITY
    Identifikatorer
    urn:nbn:se:uu:diva-37035 (URN)
    Anmärkning
    Addresses: Mankefors S, Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden. Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden. Hogskolan Skovde, Dept Nat Sci, S-54128 Skovde, Sweden. Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden.Tillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2011-11-04
    13. Hydrogen-induced changes of the electronic states in ultrathin single-crystal vanadium layers
    Öppna denna publikation i ny flik eller fönster >>Hydrogen-induced changes of the electronic states in ultrathin single-crystal vanadium layers
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    1997 (Engelska)Ingår i: PHYSICAL REVIEW B-CONDENSED MATTER, ISSN 0163-1829, Vol. 55, nr 19, s. 12914-12917Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    The electronic structure of vanadium in an Fe/V (001) superlattice, exposed to a 100 torr hydrogen pressure, was investigated using soft-x-ray emission spectroscopy and first-principles band-structure calculations. We present x-ray emission spectra from t

    Ort, förlag, år, upplaga, sidor
    AMER INST PHYSICS, 1997
    Nyckelord
    BAND
    Identifikatorer
    urn:nbn:se:uu:diva-73213 (URN)
    Anmärkning
    Addresses: UNIV UPPSALA, DEPT PHYS, S-75121 UPPSALA, SWEDEN.Tillgänglig från: 2008-10-17 Skapad: 2008-10-17 Senast uppdaterad: 2011-11-04
    14. Probing the local electronic structure in the H induced metal-insulator transition of Y
    Öppna denna publikation i ny flik eller fönster >>Probing the local electronic structure in the H induced metal-insulator transition of Y