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  • 1.
    Alfredsson, Y.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Rensmo, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Sandell, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Siegbahn, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Electronic structure of TiOPc thin film on conducting glass studied by means of X-ray and photoelectron spectroscopies2009In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 174, no 1-3, p. 50-54Article in journal (Refereed)
    Abstract [en]

    Thin films of TiOPc have been investigated using photoelectron   spectroscopy (PES) and X-ray spectroscopy (XAS). The results are   interpreted in terms of the local geometry around the metal center both   with regard to bonding and crystal field symmetry. Core and valence PES   have been found to be in accordance with the structural characteristics   of the TiOPc molecule. For resonant PES at the N1s and Ti2p edges,   information on the local electronic structure of the occupied molecular   orbitals has been obtained. Ti2p XAS was interpreted in terms of   five-fold coordination around the titanium atom for TiOPc of C-4V   symmetry. Angle-resolved N1s XAS suggests the molecular planes to order   preferentially parallel to the sample surface plane.

  • 2. Arion, Tiberiu
    et al.
    Puettner, Ralph
    Lupulescu, Cosmin
    Ovsyannikov, Ruslan
    Förstel, Marko
    Öhrwall, Gunnar
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Ueda, Kiyoshi
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Bradshaw, Alex M.
    Eberhardt, Wolfgang
    Hergenhahn, Uwe
    New insight into the Auger decay process in O-2: The coincidence perspective2012In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 185, no 8-9, p. 234-243Article in journal (Refereed)
    Abstract [en]

    Photoelectron-Auger electron coincidence spectroscopy is a powerful tool for the investigation of Auger decay processes with different core-ionized intermediate states. In this paper we describe an investigation into the Auger decay of the O-2 molecule, with the purpose of bringing new insight into the dynamics of the core hole decay mechanism. Using a novel experimental approach to measuring such coincidence spectra we report the highest resolution Auger spectrum of O-2 recorded hitherto. In our approach, we have combined the advantages of these coincidence spectra with the high resolution and excellent signal-to-noise ratios of non-coincident Auger spectra and a state-of-the-art fit analysis. In this way we have derived information about the potential energy curves of the final states W-3 Delta(u), B-3 Pi(g), and B' (3)Sigma(-)(u) and concluded that the corresponding Auger transitions are formed to a large part by strongly overlapping vibrational progressions. The present findings are compared to earlier results reported in the literature confirming some theoretical predictions.

  • 3. Balasubramanian, Padmanabhan
    et al.
    Nair, Harikrishnan. S.
    Tsai, H. M.
    Bhattacharjee, Satadeep
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Liu, M. T.
    Yadav, Ruchika
    Chiou, J. W.
    Lin, H. J.
    Pi, T. W.
    Tsai, M. H.
    Elizabeth, Suja
    Pao, C. W.
    Wang, B. Y.
    Chuang, C. H.
    Pong, W. F.
    Valence band electronic structure of Nd1-xYxMnO3 using X-ray absorption, photoemission and GGA plus U calculations2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 189, p. 51-55Article in journal (Refereed)
    Abstract [en]

    The electronic structures of Nd1-xYxMnO3 (x=0-0.5) were studied using X-ray absorption near-edge structure (XANES) at the Mn L-3,L-2- and O K-edge along with valence-band photoemission spectroscopy (VB-PES). The systematic increase in white-line intensity of the Mn L-3,L-2-edge with doping, suggests a decrease in the occupancy of Mn 3d orbitals. The O K-edge XANES shows a depletion of unoccupied states above the Fermi energy. The changes in the O K-edge spectra due to doping reflects an increase in the Jahn-Teller distortion. The VB-PES shows broadening of the features associated with Mn 3d and O 2p hybridized states and the shift of these features to a slightly higher binding energy in agreement with our GGA + U calculations. The system shows a net shift of the occupied and unoccupied states away from the Fermi energy with doping. The shift in theoretical site-projected density of states of x=0.5 composition with respect to x=0 suggest a subtle change from a charge transfer to Mott-Hubbard type insulator. (C) 2013 Elsevier B.V. All rights reserved.

  • 4.
    Bidermane, Ieva
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Brumboiu, Iulia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Physics.
    Totani, Roberta
    University of L'Aquila.
    Grazioli, Cesare
    University of Trieste.
    Shariati Nilsson, Masumeh Nina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Herper, Heike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ressel, B
    Univ Nova Gorica, Ajdovscina 5270, Slovenia.
    de Simone, Monica
    Lozzi, Luca
    University of L'Aquila.
    Brena, Barbara
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Physics.
    Puglia, Carla
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Atomic Contributions to the Valence Band Photoelectron Spectra of Metal-free, Iron and Manganese Phthalocyanines2015In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 205, p. 92-97Article, review/survey (Other academic)
    Abstract [en]

    The present work reports a photoelectron spectroscopy study of the low-energy region of the valence band of metal-free phthalocyanine (H2Pc) compared with those of iron phthalocyanine (FePc) and manganese phthalocyanine (MnPc). We have analysed in detail the atomic orbital composition of the valence band both experimentally, by making use of the variation in photoionization cross-sections with photon energy, and theoretically, by means of density functional theory. The atomic character of the Highest Occupied Molecular Orbital (HOMO), reflected on the outermost valence band binding energy region, is different for MnPc as compared to the other two molecules. The peaks related to the C 2p contributions, result in the HOMO for H2Pc and FePc and in the HOMO-1 for MnPc as described by the theoretical predictions, in very good agreement with the experimental results. The DFT simulations, discerning the atomic contribution to the density of states, indicate how the central metal atom interacts with the C and N atoms of the molecule, giving rise to different partial and total density of states for these three Pc molecules.

  • 5.
    Boutet, Sebastien
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Bogan, Michael J.
    Barty, Anton
    Frank, Matthias
    Benner, W. Henry
    Marchesini, Stefano
    Seibert, M. Marvin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Chapman, Henry N.
    Ultrafast soft X-ray scattering and reference-enhanced diffractive imaging of weakly scattering nanoparticles2008In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 166, p. 65-73Article in journal (Refereed)
    Abstract [en]

    We report the first successful reconstruction of the real space image from coherent X-ray diffraction patterns of membrane-supported nanoparticles using single ultrafast pulses. The particles consisted of 145-nm spherical polystyrene spheres that were size-selected by differential mobility analysis. We investigated the dependence of signal intensity on the number of spherical nanoparticles irradiated by single ultrafast pulses at the FLASH FEL facility. We demonstrate detection of as few as two 145-nm diameter particles irradiated by a single 32 nm fs-long FLASH pulse focused to 2.4Jcm(-2). In this case the noise in the diffraction pattern. due to photon-counting statistics and scattering from the supporting silicon nitride membrane, was the largest contributor to the recorded intensity. We were able to reconstruct high-resolution images of the nanoparticles using a strong scattering reference object to aid the phase retrieval of the coherent diffraction pattern. This method of reference-enhanced diffractive imaging may allow the imaging of weakly scattering objects at FLASH and other future X-ray FEL sources.

  • 6. Burmeister, Florian
    et al.
    Coutinho, L. H.
    Marinho, R. R. T.
    Homem, M. G. P.
    de Morais, M. A. A.
    Mocellin, A.
    Björneholm, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Sorensen, S. L.
    Fonseca, P. T.
    Lindgren, A.
    Naves de Brito, A.
    Description and performance of an electron-ion coincidence TOF spectrometer used at the Brazilian synchrotron facility LNLS2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 180, no 1-3, p. 6-13Article in journal (Refereed)
    Abstract [en]

    This paper reports the characteristics and performance of a Time-of-Flight Mass Spectrometer (TOF-MS) for coincidence measurements between electrons and ions that has been developed jointly in Sweden and Brazil. The spectrometer, used for studies of inner-shell photoexcitation of molecules in the gas-phase, has been optimized by implementing ion and electron lenses to allow the use of relatively small diameter detectors. Simulations were performed to understand the lens performance and they show that ions (electrons) could be collected without angular discrimination with a maximum kinetic energy up to ten (two) times higher than without the lens actions. A rotary vacuum chamber allows the spectrometer axis to be positioned at different angles relative to the polarization vector of the excitation beam. An important characteristic of the apparatus is that the acquisition setup allows a multi-hit capability with 1 ns resolution. Hereby, Photoelectron-Photoion-Photoion Coincidence (PEPIPICO) measurements can be performed on molecules containing two or more atoms of equal mass. A method to obtain experimental detection efficiencies of a single ion and one of one, two or three electrons has been developed. A systematic study of the interaction region has been performed to determine the shape of the photon and gas beams. Measurements on molecular nitrogen demonstrate the spectrometer's ability to resolve fragments with the same charge to mass ratio arriving within only a few ns. Simulations and experimental results of fragmentation of two singly charged cation nitrogen atoms agree, confirming that the spectrometer performance is well understood. (C) 2010 Elsevier B.V. All rights reserved.

  • 7. Ceolin, D.
    et al.
    Travnikova, O.
    Bao, Z.
    Guimaraes, F. F.
    da Costa, M. S.
    Velkov, Y.
    Sisourat, N.
    Carniato, S.
    Simon, M.
    Piancastelli, M. N.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Site-selective resonant Auger spectroscopy of iso-dichloroethylene at the carbon K-edge2012In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 185, no 8-9, p. 252-258Article in journal (Refereed)
  • 8.
    Ceolin, Denis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Travnikova, Oksana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Bao, Zhuo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Guimaraes, F. F.
    da Costa, M. S.
    Velkov, Y.
    Sisourat, N.
    Carniato, S.
    Simon, M.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Site-selective resonant Auger spectroscopy of iso-dichloroethylene at the carbon K-edge2012In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 185, no 8-9, p. 252-258Article in journal (Refereed)
    Abstract [en]

    This study focuses on the two C1s-to-LUMO (lowest unoccupied molecular orbital) excitations of the iso-dichloroethylene (H2C=CCl2) and the subsequent Auger decay. We investigate the effect of the two different carbon core excitations on the population of the cation produced after electronic relaxation. The resonant Auger spectra are interpreted by comparison to the valence shells photoionization spectrum and with the help of theoretical calculations. Several consequences of the core-hole localization on the electronic decay are observed. In particular, the resonant excitation of the C1s(CH2) to the LUMO leads to a large intensity increase in the region of the first satellite state, whereas no dramatic changes are observed for the C1s(CCl2) excitation.

  • 9.
    Ceolin, Denis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Travnikova, Oksana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Bao, Zhuo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Kivimaeki, A.
    Carniato, S.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Effect of the Cl2p core orbital excitation on the nuclear dynamics of the three dichloroethylene isomers2011In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 184, no 1-2, p. 24-28Article in journal (Refereed)
    Abstract [en]

    In this article, we present the X-ray absorption spectra of the three isomers of dichloroethylene C2H2Cl2 in the vicinity of the chlorine L-2 and L-3 edges. These isomers were excited along the first Cl2p to lowest unoccupied molecular orbital transition and an analysis of the corresponding resonant Auger spectra shows that the C-Cl bond can break before the electronic decay. An investigation of a possible Auger Doppler-like effect is also presented.

  • 10.
    CHAKAROV, DV
    et al.
    Chalmers University of Technology.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    KASEMO, B
    Chalmers University of Technology.
    INTERACTION OF WATER WITH POTASSIUM ON GRAPHITE - A HREELS STUDY1993In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 64-5, p. 279-285Article in journal (Refereed)
    Abstract [en]

    Water and coadsorbed water + potassium on the basal plane of graphite were studied with high resolution electron energy loss spectroscopy (HREELS) at 85 K and after stepwise annealing up to 500 K. Water adsorbs non-dissociatively on both clean and potassium precovered surface at 85 K. The vibration spectra, together with thermal desorption spectroscopy (TDS) reveal a series of reactions within the coadsorbed layer leading to the formation of KOH, KH, and KOx and volatile products. Eventually a precursor to CO2 formation, of yet unindentified composition and observed also in K + O-2 coadsorption studies on graphite, is observed at approximate to 27 meV.

  • 11.
    Duda, Laurent
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Oxygen redox reactions in Li ion battery electrodes studied by resonant inelastic X-ray scattering2017In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 221, p. 79-87Article in journal (Refereed)
    Abstract [en]

    We present results using inelastic scattering x-ray spectroscopy (RIXS) combined with x-ray absorption spectroscopy on Li ion battery cathode and anode materials, respectively. In particular, we discuss results obtained on the cathode materials Li1.2[Ni0.13Co0.133Mn0.544]O2 and Lix[Ni0.65Co0.25Mn0.1]O2 as well as in the composite anode material Ni0.5TiOPO4/C. We show that oxygen redox reactions are an important aspect of many such systems and how one can succesfully address them using RIXS. New insights on the formation of new oxygen species and on the details of cycling-induced structural disorder can be detected. We foresee a particular future focus on these issues considering the rapid development of new in operando RIXS techniques for Li ion battery research.

  • 12.
    Eiteneer, D.
    et al.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Pálsson, Gunna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Nemsak, S.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.;Forschungszentrum Julich, Peter Grunberg Inst PGI 6, D-52425 Julich, Germany..
    Gray, A. X.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.;SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, Menlo Pk, CA 94025 USA.;Temple Univ, Dept Phys, Philadelphia, PA 19122 USA..
    Kaiser, A. M.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Son, J.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA.;Pohang Univ Sci & Technol, Dept Mat Sci & Engn, Pohang 790784, South Korea..
    LeBeau, J.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA.;North Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA..
    Conti, G.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Greer, A. A.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.;Univ Calif Davis, Chem Engn & Mat Sci Engn, Davis, CA 95616 USA..
    Kaqi, A.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Rattanachata, A.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Saw, A. Y.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Bostwick, A.
    Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA..
    Rotenberg, E.
    Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA..
    Gullikson, E. M.
    Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA..
    Ueda, S.
    SPring 8, NIMS Beamline, Natl Inst Mat Sci, Mikazuki, Hyogo 6795148, Japan.;Natl Inst Mat Sci, Quantum Beam Unit, Tsukuba, Ibaraki 3050047, Japan..
    Kobayashi, K.
    SPring 8, NIMS Beamline, Natl Inst Mat Sci, Mikazuki, Hyogo 6795148, Japan.;Japan Atom Energy Agcy, Mikazuki, Hyogo 6795148, Japan..
    Janotti, A.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA..
    Van de Walle, C. G.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA..
    Blanca-Romero, A.
    Univ Munich, Dept Earth & Environm Sci, Sect Crystallog, D-80333 Munich, Germany.;Univ Munich, Ctr Nanosci, D-80333 Munich, Germany.;Imperial Coll London, Thomas Young Ctr, Dept Chem, London SW7 2AZ, England..
    Pentcheva, R.
    Univ Duisburg Essen, Thebret Phys, D-47057 Duisburg, Germany.;Ctr Nanointegrat CENIDE, D-47057 Duisburg, Germany.;Univ Munich, Dept Earth & Environm Sci, Sect Crystallog, D-80333 Munich, Germany.;Univ Munich, Ctr Nanosci, D-80333 Munich, Germany..
    Schneider, C. M.
    Forschungszentrum Julich, Peter Grunberg Inst PGI 6, D-52425 Julich, Germany..
    Stemmer, S.
    Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA..
    Fadley, C. S.
    Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
    Depth-Resolved Composition and Electronic Structure of Buried Layers and Interfaces in a LaNiO3/SrTiO3 Superlatticefroni Soft- and Hard-X-ray Standing-Wave Angle-Resolved Photoemission2016In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 211, p. 70-81Article in journal (Refereed)
    Abstract [en]

    LaNiO3 (LNO) is an intriguing member of the rare-earth nickelates in exhibiting a metal-insulator transition for a critical film thickness of about 4 unit cells [Son et al., Appl. Phys. Lett. 96, 062114 (2010)]; however, such thin films also show a transition to a metallic state in superlattices with SrTiO3 (STO) [Son et al., Appl. Phys. Lett. 97, 202109 (2010)]. In order to better understand this transition, we have studied a strained LNO/STO superlattice with 10 repeats of [4 unit-cell LNO/3 unit-cell STO] grown on an (LaAlO3)(0.3)(Sr2AlTaO6)(0.7) substrate using soft x-ray standing-wave-excited angle-resolved photoemission (SWARPES), together with soft- and hard- x-ray photoemission-measurements of core levels and densities-of-states valence spectra. The experimental results are compared with state-of-the-art density functional theory (DFT) calculations of band structures and densities of states. Using core-level rocking curves and x-ray optical modeling to assess the position of the standing wave, SWARPES measurements are carried out for various incidence angles and used to determine interface-specific changes in momentum-resolved electronic structure. We further show that the momentum-resolved behavior of the Ni 3d e(g) and t(2g) states near the Fermi level, as well as those at the bottom of the valence bands, is very similar to recently published SWARPES results for a related La0.7Sr0.3MnO3/SrTiO3 superlattice that was-studied using the same technique (Gray et al., Europhysics Letters 104, 17004 (2013)), which further validates this experimental approach and our conclusions. Our conclusions are also supported in several ways by comparison to DFT calculations for the parent materials and the superlattice, including layer-resolved density-of-states results.

  • 13.
    Feifel, Raimund
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Core-level spectroscopy and dynamics of free molecules2011In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 183, no 1-3, p. 10-28Article in journal (Refereed)
    Abstract [en]

    A review of recent results on spectroscopy and dynamics of free molecules is presented. The experimental research reported here is mainly concerned with processes of core excitation and decay of isolated molecules, primarily investigated by resonant Auger spectroscopy. Several examples are shown concerning the interplay of the timescales of electron decay with nuclear motion involving dissociation processes, the occurrence of interference phenomena and recoil. The capability of such studies to reveal subtle details of the light-matter interaction, of the electronic structure and of the evolution of the short-lived states thus created is enlightened.

  • 14.
    Fondell, Mattis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, Berlin 12489, Germany.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    An HAXPES study of Sn, SnS, SnO and SnO22014In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 195, p. 195-199Article in journal (Refereed)
    Abstract [en]

    Hard X-ray photoelectron spectra have been recorded for Sn, SnO2, SnO and SnS. The binding energies of the core levels of elemental Sn from 2s up to, and including, 4d have been determined with least squares fitting and calibrated against an Au 4f standard. For the oxides and the sulphide data on Sn 3p, 3d core levels’ binding energies and relative intensities are presented together with the binding energies of O 1s, S 1s and 2p. This study thus serves as a picture of tin's core level spectra compared to those of some of its oxides and a sulphide taken at photon energies beyond Al Kα and Mg Kα.

  • 15.
    Fondell, Mattis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, Berlin 12489, Germany.
    Gorgoi, Mihaela
    Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, Berlin 12489, Germany.
    Boman, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, Berlin 12489, Germany.
    Surface modification of iron oxides by ion bombardment – comparing depth profiling by HAXPES and Ar ion sputtering2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 23-26Article in journal (Refereed)
    Abstract [en]

    Iron oxide in the form of maghemite  γ-Fe2O3  and hematite α-Fe2O3 has been studied with x-ray photoelectron spectroscopy. It is found that even low energy sputtering induces a reduction of the surface layer into FeO. Satellites in the Fe 2p  core level spectra are used to determine the oxidation state of iron. Depth profiling with changing photon energy shows that the unsputtered films are homogeneous and that the information obtained from sputtering thus, in this instance, represents sputter damages to the sample.

  • 16. Förstel, Marko
    et al.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Anon, Tiberiu
    Lischke, Toralf
    Barth, Silko
    Ulrich, Volker
    Öhrwall, Gunnar
    Björneholm, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Hergenhahn, Uwe
    Bradshaw, Alex M.
    Energy band dispersion in photoemission spectra of argon clusters2011In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 184, no 3-6, p. 107-112Article in journal (Refereed)
    Abstract [en]

    Using photoemission we have investigated free argon clusters from a supersonic nozzle expansion in the photon energy range from threshold up to 28 eV. Measurements were performed both at high resolution with a hemispherical electrostatic energy analyser and at lower resolution with a magnetic bottle device. The latter experiments were performed for various mean cluster sizes. In addition to the approximate to 15eV broad 3p-derived valence band seen in previous work, there is a sharper feature at approximate to 15eV binding energy. Surprisingly for non-oriented clusters, this peak shifts smoothly in binding energy over the narrow photon energy range 15.5-17.7 eV, indicating energy band dispersion. The onset of this bulk band-like behaviour could be determined from the cluster size dependence.

  • 17.
    Giangrisostomi, Erika
    et al.
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-72489 Berlin, Germany..
    Ovsyannikov, Ruslan
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-72489 Berlin, Germany..
    Sorgenfrei, Florian
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Zhang, Teng
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Lindblad, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Sassa, Yasmine
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Cappel, Ute B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Leitner, Torsten
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Mitzner, Rolf
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-72489 Berlin, Germany..
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Foehlisch, Alexander
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-72489 Berlin, Germany.;Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Low Dose Photoelectron Spectroscopy at BESSY II: Electronic structure of matter in its native state2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 68-78Article in journal (Refereed)
    Abstract [en]

    The implementation of a high-transmission, angular-resolved time-of-Right electron spectrometer with a 1.25 MHz pulse selector at the PM4 soft X-ray dipole beamline of the synchrotron BESSY II creates unique capabilities to inquire electronic structure via photoelectron spectroscopy with a minimum of radiation dose. Solid-state samples can be prepared and characterized with standard UHV techniques and rapidly transferred from various preparation chambers to a 4-axis temperature-controlled measurement stage. A synchronized MHz laser system enables excited-state characterization and dynamical studies starting from the picosecond timescale. This article introduces the principal characteristics of the PM4 beamline and LowDosePES end-station. Recent results from graphene, an organic hole transport material for solar cells and the transition metal dichalcogenide MoS2 are presented to demonstrate the instrument performances. (C) 2017 The Authors. Published by Elsevier B.V.

  • 18. Glover, C.J.
    et al.
    Schmitt, T
    Mattesini, M
    Adell, M
    Ilver, L
    Kanski, J
    Kjeldgaard, L
    Agåker, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Mårtensson, N
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Surface and Interface Science.
    Ahuja, R
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Nordgren, J
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Rubensson, J.-E.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
    Stationary and dispersive features in resonant inelastic soft X-ray scattering at the Ge 3p resonances2009In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 173, no 2-3, p. 103-107Article in journal (Refereed)
    Abstract [en]

    Resonant inelastic soft X-ray scattering at the 3p resonances in crystalline Ge is presented. Both stationary and dispersive features are observed in a wide energy range above as well as below the ionization limits. These observations are in agreement with theoretical predictions based on a two-step model where the initially excited electron has no influence on the emission step. Excess population of states in the conduction band is found, and discussed in terms of attosecond electron dynamics. (c) 2009 Elsevier B.V. All rights reserved.

  • 19. Gorgoi, M.
    et al.
    Karis, O.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Svensson, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Ohrwall, G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Andersson, G.
    Marcellini, M.
    Martensson, N.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Olovsson, W.
    Holmstrom, E.
    Abrikosov, I. A.
    Niklasson, A. M. N.
    Johansson, B.
    Braun, W.
    Bressler, P.
    Schafers, E.
    Eberhardt, W.
    A non-destructive deep interface characterization technique for multilayer films2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 156, p. LII-LIIArticle in journal (Refereed)
  • 20.
    Gorgoi, M.
    et al.
    HZB-Berlin.
    Schaefers, F.
    HZB-Berlin.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Relative sub-shell photoionization cross-sections of nickel metal determined by hard X-ray high kinetic energy photoemission2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 190, p. 153-158Article in journal (Refereed)
    Abstract [en]

    Recently, hard X-ray high kinetic energy photoelectron spectroscopy has lead to a break-through due to its non destructive way of investigating the bulk electronic properties of materials. However, due to the relatively new development of this technique there is a lack of information concerning the photoionization cross sections at high energies. Whenever compound materials are investigated or when estimating signal levels and the feasibility of an electron spectroscopy experiment the knowledge of cross sections is essential. In the present work the experimentally determined relative sub-shell photoionization cross sections of shallow levels of nickel metal in the energy range of 2-9 keV will be shown. The data are compared with calculated sub-shell photoionization cross sections.

  • 21.
    Gorgoi, Mihaela
    et al.
    Helmholtz Zentrum Berlin Mat & Energie, D-12489 Berlin, Germany..
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    HAXPES studies of solid materials for applications in energy and information technology using the HIKE facility at HZB-BESSY II2015In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 200, p. 40-48Article in journal (Refereed)
    Abstract [en]

    In the present work we review a number of research directions addressed at the HIKE end-station at the BESSY II storage ring at the Helmholtz-Zentrum Berlin, HZB, using hard X-ray photoelectron spectroscopy (HAXPES). The emphasis of this review is on the specific properties of the technique, which are required in order to address different scientific questions at the HIKE beamline.

  • 22.
    Granroth, Sari
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Olovsson, Weine
    Holmström, Erik
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Gorgoi, Mihaela
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Understanding interface properties from high kinetic energy photoelectron spectroscopy and first principles theory2011In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 183, no 1-3, p. 80-93Article, review/survey (Refereed)
    Abstract [en]

    Advances in instrumentation regarding 3rd generation synchrotron light sources and electron spectrometers has enabled the field of high kinetic energy photoelectron spectroscopy (HIKE) (also often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES)). Over the last years, the amount of investigations that relies on the HIKE method has increased dramatically and can arguably be said to have given a rebirth of the interest in photoelectron spectroscopy in many areas. It is in particular the much increased mean free path at higher kinetic energies in combination with the elemental selectivity of the core level spectroscopies in general that has lead to this fact, as it makes it possible to investigate the electronic structure of materials with a substantially reduced surface sensitivity. In this review we demonstrate how HIKE can be used to investigate the interface properties in multilayer systems. Relative intensities of the core level photoelectron peaks and their chemical shifts derived from binding energy changes are found to give precise information on physico-chemical properties and quality of the buried layers. Interface roughening, including kinetic properties such as the rate of alloying, and temperature effects on the processes can be analyzed quantitatively. We will also provide an outline of the theoretical framework that is used to support the interpretation of data. We provide examples from our own investigations of multilayer systems which comprises both systems of more model character and a multilayer system very close to real applications in devices that are considered to be viable alternative to the present read head technology. The experimental data presented in this review is exclusively recorded at the BESSY-II synchrotron at the Helmholtz-Zentrum Berlin fur-Materialien und Energie. This HIKE facility is placed at the bending magnet beamline KMC-1, which makes it different from several other facilities which relies on undulators as the source. We will therefore also briefly describe some of the salient design features of this facility.

  • 23.
    Guillemin, Renaud
    et al.
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Carniato, Stephane
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Journel, Loic
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Stolte, Wayne C.
    Univ Nevada, Dept Chem, Las Vegas.
    Marchenko, Tatiana
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    El Khoury, Lara
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Kawerk, Elie
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    Hudson, Amanda C.
    Univ Nevada, Dept Chem, Las Vegas.
    Lindle, Dennis W.
    Univ Nevada, Dept Chem, Las Vegas.
    Simon, Marc
    UPMC Univ Paris 06, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.; CNRS, UMR 7614, Lab Chim Phys Mat & Rayonnement, Paris.
    A review of molecular effects in gas-phase KL X-ray emission2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 188, p. 53-61Article, review/survey (Refereed)
    Abstract [en]

    The unique capabilities of resonant inelastic X-ray scattering (RIXS) to provide a deep insight into molecular dynamics following core excitation are reviewed here. Characteristic features of molecular X-ray emission are experimentally observed and theoretically interpreted. Some of our most significant results on molecular dynamics following deep core excitation are presented. In particular, we provide several examples of nuclear dynamics on the femtosecond or subfemtosecond time scale; line-narrowing effects related to the quenching of vibrational structure due to parallelism of intermediate and final state curves; anomalous line dispersion across a resonance, which is due to core-hole lifetime effects; spin–orbit-state populations derived from polarized RIXS experiments. We also show how to connect the RIXS results to the general chemical properties of the investigated systems.

  • 24. Guo, J. -H
    et al.
    Kastanov, S.
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Glans, P. -A
    West, M.
    Learmonth, T.
    Chiou, J. -W
    Luo, Y.
    Nordgren, J.
    Smith, K.
    Pong, W. -F
    Cheng, H.
    Griffiss, J. M.
    Electronic structure study of the bases in DNA duplexes by in situ photon-in/photon-out soft X-ray spectroscopy2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 181, no 2–3, p. 197-201Article in journal (Refereed)
  • 25. Guo, J. -H
    et al.
    Kastanov, S.
    Söderström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Glans, P. -A
    West, M.
    Learmonth, T.
    Chiou, J. -W
    Luo, Yi
    Nordgren, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Smith, K.
    Pong, W. -F
    Cheng, H.
    Griffiss, J. M.
    Electronic structure study of the bases in DNA duplexes by in situ photon-in/photon-out soft X-ray spectroscopy2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 181, no 2-3, p. 197-201Article in journal (Refereed)
    Abstract [en]

    Understanding protein functionality is of fundamental importance in biochemistry. Soft X-ray transitions, where the core-level vacancies are filled by the valence-orbital electrons, give direct information about the chemical bonding. Soft X-ray absorption and emission study of poly(dG) -poly(dC) in aqueous solutions can elucidate the relation between the structure and functionality of proteins. We report the N K-edge soft X-ray absorption (XAS) and resonant soft X-ray emission spectroscopy (XES) to characterize the electronic structure near the Fermi level of DNA duplexes to specify the charge migration mechanism. Since N atoms are included in only bases in DNA duplexes, the XES spectra excited from N Is to unoccupied states purely extract the electronic orbital features of the bases in DNA. The fact that N atoms in different bonding environments form well-defined structure has been determined. The experimental findings provide the evidence for the charge-hopping and/or charge-transfer effects in understanding of electric conduction in DNA duplexes when electrons pass through the pi* states of DNA bases. (C) 2010 Elsevier B.V. All rights reserved.

  • 26. Harnes, J.
    et al.
    Abu-samhaa, M.
    Winkler, M.
    Bergersen, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Saethre, L. J.
    Borve, K. J.
    Neutral CH3Cl and CH3Br clusters studied by X-ray photoelectron spectroscopy and modeling: Insight to intermolecular interactions and structure2008In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 166, p. 53-64Article in journal (Refereed)
    Abstract [en]

    Single-component clusters of methyl chloride and methyl bromide have been produced by adiabatic expansion and their C 1s, Cl 2p and Br 3d photoelectron spectra recorded using synchrotron radiation and a high-resolution electron analyzer. The experimentally observed cluster-to-monomer shifts in core-level ionization energies are interpreted in terms of theoretical models based on molecular dynamics (MD) in conjunction with polarizable force fields developed and validated in the course of this work. MD simulations have also been used to explore the global and local structure of the clusters, providing evidence for a predominance of anti-parallel, head-to-tail arrangement of neighboring molecules. Whereas the cluster-to-monomer shifts are strongly dominated by polarization effects, the polarization contribution is very similar for ionization of carbon and the halogen, respectively. The difference in cluster shifts between the two ionization sites within the same molecule, C vs. Cl or C vs. Br, is thus determined by permanent electrostatic moments, i.e. the magnitude and direction of the permanent dipole moment and the local alignment of dipoles.

  • 27. Huttula, Marko
    et al.
    Mikkelae, Mikko-Heikki
    Tchaplyguine, Maxim
    Björneholm, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Size-varied photoelectron spectroscopy of metal clusters using the Exchange Metal Cluster Source2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 181, no 2-3, p. 145-149Article in journal (Refereed)
    Abstract [en]

    The recently developed Exchange Metal Cluster Source (EXMEC) is described. The source is designed for electron-spectroscopic studies of neutral metal clusters. Preliminary results on the rubidium and tin clusters using synchrotron radiation excited photoelectron spectroscopy show the capability for cluster production in the size regime of few tens to few hundred of atoms per cluster. A wide range of metal evaporation temperatures is covered applying resistive and induction heating methods. (C) 2010 Elsevier B.V. All rights reserved.

  • 28. Jänkälä, K.
    et al.
    Schulz, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Aksela, H.
    Shake-up satellites accompanying the inner shell ionization of alkali atoms2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 161, no 1-3, p. 95-98Article in journal (Refereed)
    Abstract [en]

    The shake-up probabilities of the outermost electron in inner shell ionization and subsequent Auger decay of alkali atoms have been studied in the sudden approximation model using the wavefunctions obtained with the multiconfiguration Dirac-Fock (MCDF) method. The tendencies of the shake-up probabilities for both the initially excited and the nonexcited configurations were found to be predicted well in the photoionization by the model used. Based on the calculations, the second shake-up during Auger decay was found to receive considerable high intensity.

  • 29.
    Kahk, J. Matthias
    et al.
    Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2AZ, England..
    Villar-Garcia, Ignacio J.
    Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2AZ, England..
    Grechy, Lorenza
    Univ London Imperial Coll Sci Technol & Med, Dept Aeronaut, London SW7 2AZ, England..
    Bruce, Paul J. K.
    Univ London Imperial Coll Sci Technol & Med, Dept Aeronaut, London SW7 2AZ, England..
    Vincent, Peter E.
    Univ London Imperial Coll Sci Technol & Med, Dept Aeronaut, London SW7 2AZ, England..
    Eriksson, Susanna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Ahlund, John
    VG Scienta AB, S-75015 Uppsala, Sweden..
    Edwards, Marten O. M.
    VG Scienta AB, S-75015 Uppsala, Sweden..
    Payne, David J.
    Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2AZ, England..
    A study of the pressure profiles near the first pumping aperture in a high pressure photoelectron spectrometer2015In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 205, p. 57-65Article in journal (Refereed)
    Abstract [en]

    In a high-pressure photoelectron spectrometer, the sample is positioned close to a differential pumping aperture, behind which the pressure is several orders of magnitude lower than the pressure in the analysis chamber. To find the optimal sample position, where the path length of the photoelectrons through the high pressure region is minimized as far as possible without compromising knowledge of the actual pressure at the sample surface, an understanding of the pressure variations near the sample and the aperture is required. A computational fluid dynamics study has been carried out to examine the pressure profiles, and the results are compared against experimental spectra whose intensities are analyzed using the Beer-Lambert law. The resultant pressure profiles are broadly similar to the one previously derived from a simplistic molecular flow model, but indicate that as the pressure in the analysis chamber is raised, the region over which the pressure drop occurs becomes progressively narrower.

  • 30.
    Kawerk, Elie
    et al.
    Univ Paris 06, Lab Chim Phys Mat & Rayonnement, Paris.; Univ Libanaise, Fac Sci Fanar 2, Lab Phys Appl, Lebanon.
    Carniato, Stephane
    Univ Paris 06, Lab Chim Phys Mat & Rayonnement, Paris.
    Iwayama, Hiroshi
    Natl Inst Nat Sci, Inst Mol Sci, Ultraviolet Synchrotron Orbital Radiat Facil, Okazaki.
    Shigemasa, Eiji
    Natl Inst Nat Sci, Inst Mol Sci, Ultraviolet Synchrotron Orbital Radiat Facil, Okazaki.
    Piancastelli, Maria Novella
    Univ Paris 06, Lab Chim Phys Mat & Rayonnement, Paris.
    Wassaf, Joseph
    Univ Libanaise, Fac Sci Fanar 2, Lab Phys Appl, Lebanon.
    Khoury, Antonio
    Univ Libanaise, Fac Sci Fanar 2, Lab Phys Appl, Lebanon.
    Simon, Marc
    Univ Paris 06, Lab Chim Phys Mat & Rayonnement, Paris.
    Experimental and theoretical study of X-ray absorption around the chlorine L edge in vinyl chloride2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 186, p. 1-7Article in journal (Refereed)
    Abstract [en]

    We present a combined experimental and theoretical study of the high-resolution chlorine L edge X-ray absorption spectrum in gas-phase vinyl chloride (C2H3Cl). With the help of ab-initio calculations, we interpret the experimental spectrum and attribute each band to its corresponding electronic transitions terminating at states characterized by an either binding or dissociative potential energy surface (PES). Vibrational substructures in some specific core-excited electronic states are taken into account.

  • 31.
    Knut, Ronny
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Lindblad, Rebecka
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gorgoi, Mihaela
    Rensmo, Hakan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    High energy photoelectron spectroscopy in basic and applied science: Bulk and interface electronic structure2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 190, p. 278-288Article in journal (Refereed)
    Abstract [en]

    With the access of new high-performance electron spectrometers capable of analyzing electron energies up to the order of 10 keV, the interest for photoelectron spectroscopy has grown and many new applications of the technique in areas where electron spectroscopies were considered to have limited use have been demonstrated over the last few decades. The technique, often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES), to distinguish the experiment from X-ray photoelectron spectroscopy performed at lower energies, has resulted in an increasing interest in photoelectron spectroscopy in many areas. The much increased mean free path at higher kinetic energies, in combination with the elemental selectivity of the core level spectroscopies in general has led to this fact. It is thus now possible to investigate the electronic structure of materials with a substantially enhanced bulk sensitivity. In this review we provide examples from our own research using HAXPES which to date has been performed mainly at the HIKE facility at the KMC-1 beamline at HZB, Berlin. The review exemplifies the new opportunities using HAXPES to address both bulk and interface electronic properties in systems relevant for applications in magnetic storage, energy related research, but also in purely curiosity driven problems.

  • 32. Kotani, A.
    et al.
    Kvashnina, Kristina O.
    Butorin, Sergei M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Glatzel, P.
    A new method of directly determining the core-hole effect in the Ce L-3 XAS of mixed valence Ce compounds: An application of resonant X-ray emission spectroscopy2011In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 184, no 3-6, p. 210-215Article in journal (Refereed)
    Abstract [en]

    Using a simplified model, we calculate resonant X-ray emission (RXE) spectra with Ce 2p to 5d excitation and Ce nl to 2p de-excitation for mixed valence Ce compounds, where nl is 3d or valence states. If the core-hole effect is large to play an important role in the Ce L-3 XAS, the RXE spectral features for nl = 3d and valence states are significantly different, but if it is negligibly small, they are essentially the same. Therefore, these RXE spectra are useful as a new powerful method of directly determining the core-hole effect in the L-3 XAS. More detailed theoretical calculations of these RXE spectra are made for CeO2, and compared with new experimental data, indicating the importance of the core-hole effect. Similar investigations are desirable for some metallic mixed valence Ce compounds in which the core-hole effect is controversial. Finally, we point out that for nl = 5d we can observe the resonant inelastic X-ray scattering spectra corresponding to the charge-transfer excitations or Kondo resonance excitations.

  • 33.
    Kuehn, Danilo
    et al.
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.;Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Sorgenfrei, Florian
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.;Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Giangrisostomi, Erika
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Jay, Raphael
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Musazay, Abdurrahman
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Ovsyannikov, Ruslan
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Stråhlman, Christian
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany.;Malmo Univ, S-20506 Malmo, Sweden..
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden..
    Foehlisch, Alexander
    Univ Potsdam, Inst Phys & Astron, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany.;Helmholtz Zentrum Berlin Mat & Energie GmbH, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Capabilities of Angle Resolved Time of Flight electron spectroscopy with the 60 degrees wide angle acceptance lens2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 45-50Article in journal (Refereed)
    Abstract [en]

    The simultaneous detection of energy, momentum and temporal information in electron spectroscopy is the key aspect to enhance the detection efficiency in order to broaden the range of scientific applications. Employing a novel 60 degrees wide angle acceptance lens system, based on an additional accelerating electron optical element, leads to a significant enhancement in transmission over the previously employed 30 degrees electron lenses. Due to the performance gain, optimized capabilities for time resolved electron spectroscopy and other high transmission applications with pulsed ionizing radiation have been obtained. The energy resolution and transmission have been determined experimentally utilizing BESSY II as a photon source. Four different and complementary lens modes have been characterized. (C) 2017 The Authors. Published by Elsevier B.V.

  • 34. Kvashnina, K. O.
    et al.
    Kvashnin, Yaroslav
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Butorin, Sergei
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Role of resonant inelastic X-ray scattering in high-resolution core-level spectroscopy of actinide materials2014In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 194, p. 27-36Article in journal (Refereed)
    Abstract [en]

    This paper provides a brief overview of applications of advanced X-ray spectroscopic techniques that take advantage of the resonant inelastic X-ray scattering (RIXS) in the hard and tender X-ray range and have recently become available for studying the electronic structure of actinides. We focus here on the high-energy-resolution X-ray absorption near edge structure (XANES) and core-to-core and core-to-valence RIXS spectroscopies at the U L and M edges of uranium compounds. The spectral features are analyzed using a number of theoretical methods, such as the Anderson impurity model, density functional theory in the local density approximation with an added Coulomb interaction (LDA + U), and full multiple scattering (FEFF) and ab initio finite difference method near-edge structure (FDMNES) codes. In connection with presented results, the capabilities and limitations of the experimental techniques and theoretical methods are discussed. (C) 2014 Elsevier B.V. All rights reserved.

  • 35. Laukkanen, P.
    et al.
    Punkkinen, M. P. J.
    Ahola-Tuomi, M.
    Lang, J.
    Schulte, K.
    Pietzsch, A.
    Kuzmin, M.
    Sadowski, J.
    Adell, J.
    Perala, R. E.
    Ropo, M.
    Kokko, K.
    Vitos, Levente
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Johansson, Börje
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Pessa, M.
    Vayrynen, I. J.
    Core-level shifts of the c(8 x 2)-reconstructed InAs(100) and InSb(100) surfaces2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 177, no 1, p. 52-57Article in journal (Refereed)
    Abstract [en]

    We have studied In-stabilized c(8 2)-reconstructed InAs(1 0 0) and InSb(1 0 0) semiconductor surfaces, which play a key role in growing improved III-V interfaces for electronics devices, by core-level photoelectron spectroscopy and first-principles calculations. The calculated surface core-level shifts (SCLSs) for the zeta and zeta a models, which have been previously established to describe the atomic structures of the III-V(1 00)c(8 x 2) surfaces, yield hitherto not reported interpretation for the As 3d, In 4d, and Sb 4d core-level spectra of the III-V(1 00)c(8 x 2) surfaces, concerning the number and origins of SCLSs. The fitting analysis of the measured spectra with the calculated zeta and zeta a SCLS values shows that the InSb spectra are reproduced by the zeta SCLSs better than by the zeta a SCLSs. Interestingly, the zeta a fits agree better with the InAs spectra than the zeta fits do, indicating that the zeta a model describes the InAs surface better than the InSb surface. These results are in agreement with previous X-ray diffraction data. Furthermore, an introduction of the complete-screening model, which includes both the initial and final state effects, does not improve the fitting of the InSb spectra, proposing the suitability of the initial-state model for the SCLSs of the III-V(1 0 0)c(8 x 2) surfaces. The found SCLSs are discussed with the ab initio on-site charges. (C) 2010 Elsevier B.V. All rights reserved.

  • 36.
    Lindblad, Rebecka
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Oscarsson, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Fredin, Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Eriksson, Susanna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Controlling energy level positions in hole conducting molecular films by additives2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 100-106Article in journal (Refereed)
    Abstract [en]

    Hard X-ray photoelectron spectroscopy (HAXPES) has been used to study the bulk electronic structure of thin molecular films of the organic compounds 2,2',7,7'-tetrakis (N,N'-di-p-methoxyphenyl-amine)-9,9'-spiro-bifluorene (spiro-OMeTAD), 4-(diethylamino)-benzaldehyde-1,1-diphenyl-hydrazone (DEH) and poly(3-hexylthiophene) (P3HT). Molecular layers of these compounds are hole conducting, a property that for example has been used in different solar cell configurations. The function of such a device benefits from the inclusion of additives such as Li-TFSI, or dopants such as Co-complexes, into the molecular layer. Here we report on effects of adding Li-TFSI to DEH and P3HT as observed by photoelectron spectroscopy and we compare with results on the spiro-OMeTAD hole conductor. It can be concluded that the Li-salt causes a shift of the Fermi level in DEH and P3HT towards the HOMO resulting in a p-doping of the molecular material. Similar shifts of the Fermi level could also be observed when adding different Co(+III) complexes to the Spiro-OMeTAD hole conductor, indicating means for more controlled doping.

  • 37.
    Lundwall, M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Pokapanich, W.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Bergersen, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Rander, T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Lindblad, A.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Ohrwall, G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Tchaplyguine, M.
    Svensson, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Bjorneholm, O.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Cluster formation and structure after co-expansion of argon and neon studied by electron spectroscopies2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 156, p. LXXI-LXXIArticle in journal (Refereed)
  • 38.
    Magnuson, Martin
    et al.
    Linkoping Univ, IFM, Dept Phys Chem & Biol, Thin Film Phys Div, SE-58183 Linkoping, Sweden..
    Schmitt, Thorsten
    SLS, Paul Scherrer Inst, Res Dept Synchrotron Radiat & Nanotechnol, CH-5232 Villigen, Switzerland..
    Duda, Laurent-C.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Polarization-dependent resonant inelastic X-ray scattering study at the Cu L and O K-edges of YBa2Cu3O7-x2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 38-44Article in journal (Refereed)
    Abstract [en]

    We present a study on the high-Tc superconductor (HTSC) YBa2Cu3O7-x (YBCO) using polarization dependent X-ray absorption and resonant inelastic X-ray scattering. High-resolution measurements using synchrotron-radiation are compared with calculations using a quasi-atomic multiplet approach performed at the Cu 2p(3/2)-edge of YBCO. We use a multiplet approach within the single impurity Anderson model to reproduce and understand the character of the localized low-energy excitations in YBCO. We observe a distinct peak at about 0.5 eV in OK RIXS. This peak shows dependence on doping, incident energy, and momentum transfer that suggests that it has a different origin than the previously discussed cuprate bimagnons. Therefore, we assign it to bimagnon excitations within the Zhang Rice bands and/or the Upper Hubbard bands, respectively. (C) 2017 Elsevier B.V. All rights reserved.

  • 39.
    Magnuson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Yang, L
    Guo, JH
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Såthe, Conny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Agui, A
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Nordgren, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Luo, Y
    Ågren, Hans
    Johansson, N
    Salaneck, WR
    Horsburgh, LE
    Monkman, AP
    Resonant inelastic soft X-ray scattering spectra at the nitrogen and carbon K-edges of poly(pyridine-2,5-diyl)1999In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 101-103, p. 573-578Article in journal (Refereed)
    Abstract [en]

    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.

  • 40. Marinho, R. R. T.
    et al.
    Ohrwall, G.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Bergersen, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Pokapanich, W.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Naves de Brito, A.
    Svensson, S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics, Physics V.
    Bjorneholm, O.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Liquid beam source for synchrotron radiation based photoelectrons spectroscopy2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 156, p. LI-LIArticle in journal (Refereed)
  • 41.
    Massel, Felix
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Ahmadi, Sareh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Liu, Y.-S
    Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA, USA.
    Guo, J.-H.
    Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA, USA.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Duda, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Transition metal doping effects in Co-phosphate catalysts for water splitting studied with XAS2018In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, p. 3-7Article in journal (Refereed)
    Abstract [en]

    Metal oxides as oxygen evolution reaction (OER) catalysts for water splitting are ubiquitous in research and application. Pure and doped (or hybrid) Co oxide systems are of particular interest due to their good efficiency. However, the electronic effects of different dopants are still unclear in many of these systems. We present a study of doped Co-phosphate (P-i) films deposited electrochemically from aqueous solutions of neutral pH using an X-ray absorption spectroscopy (XAS), a technique that can reveal important information about catalytically active states. These hybrid films, obtained from solutions containing both Co ions and another transition metal (TM) ion (TM = Mn, Fe, Ni), were analyzed with XAS at the TM L-edges and the O K-edge. We find that a large concentration of Co3+-ions in the films and a low-lying edge of the O 2p conduction band (CB) are good indicators for the OER efficiency of the films. Our results show that native Co-P-i is close to optimal for the OER activity at low deposition potential. However, Mn- and Ni-doped systems have promising properties when deposited at higher potentials because these ions tend to stabilize the Co3+-state in the films as well as the position of the O 2p-edge CB (a few tenths of 1 eV), in contrast to native Co-Pi films.

  • 42. Mazumdar, Dipanjan
    et al.
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Thöle, F.
    Gorgoi, M.
    Faleev, Sergei
    Mryasov, O. N.
    Shelke, Vilas
    Ederer, C.
    Spaldin, N. A.
    Gupta, A.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    The valence band electronic structure of rhombohedral-like and tetragonal-like BiFeO3 thin films from hard X-ray photoelectron spectroscopy and first-principles theory2016In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 208, p. 63-66Article in journal (Refereed)
    Abstract [en]

    Abstract We investigate the electronic structure of rhombohedral-like (R) and tetragonal-like (T) BiFeO3 thin films using high energy X-ray photoelectron spectroscopy and first-principles electronic structure calculations. By exploiting the relative elemental cross sections to selectively probe the elemental composition of the valence band, we identify a strong Bi 6p contribution at the top of the valence band in both phases, overlapping in energy range with the O 2p states; this assignment is confirmed by our electronic structure calculations. We find that the measured occupied Bi 6p signal lies closer to the top of the valence band in the T phase than in the R phase, which we attribute, using our electronic structure calculations, to lower Bi–O hybridization in the T phase. We note, however, that our calculations of the corresponding densities of states underestimate the difference between the phases, suggesting that matrix element effects resulting from the different effective symmetries also contribute. Our results shed light on the chemical nature of the stereochemically active Bi lone pairs, which are responsible for the large ferroelectric polarization of BiFeO3.

  • 43.
    Mucke, Melanie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Arion, T.
    Max Planck Inst Plasma Phys, D-85748 Garching, Germany.;Ctr Free Electron Laser Sci DESY, D-22607 Hamburg, Germany..
    Foerstel, M.
    Max Planck Inst Plasma Phys, D-85748 Garching, Germany..
    Lischke, T.
    Max Planck Inst Plasma Phys, D-85748 Garching, Germany..
    Hergenhahn, U.
    Max Planck Inst Plasma Phys, D-17491 Greifswald, Germany..
    Competition of inelastic electron scattering and Interatomic Coulombic Decay in Ne clusters2015In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 200, p. 232-238Article in journal (Refereed)
    Abstract [en]

    The creation of slow electrons due to Interatomic Coulombic Decay of 2s vacancies in Ne clusters is quantitatively compared to the slow electron yield by intracluster electron impact ionization. Using electron-electron coincidence spectroscopy, both channels can be separated experimentally. Two cluster size distributions, corresponding to two and five to six filled solvation shells, are probed.

  • 44. Mundim, Maria S. P.
    et al.
    Mocellin, Alessandra
    Makiuchi, Nilo
    Naves de Brito, Arnaldo
    Attie, Marcia
    Correia, Nestor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry, Quantum Chemistry.
    Study of thiophene inner shell photofragmentation2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 155, no 1-3, p. 58-63Article in journal (Refereed)
    Abstract [en]

    We investigated the inner shell photofragmentation of thiophene by time of flight (TOF) mass spectroscopy using multi-coincidence electron-ion techniques. Our main purpose was to understand aspects of molecular relaxation process after inner shell excitation and to search for bond break selectivity. Analyses of mass and branching ratios are presented and the results suggest different mechanisms and channel of fragmentation when compared with S 2p and C 1s excitations.

  • 45. Määttä, M.
    et al.
    Schultz, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics.
    Heinäsmäki, S.
    Aksela, H.
    Valence photoelectron spectra of Na, K, Rb and Cs with s or p outermost electron: Evolution of the states from LS-coupling to jK-coupling2007In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 161, no 1-3, p. 99-104Article in journal (Refereed)
    Abstract [en]

    The development of the fine structure of the np(5)(n + 1)s and np(5)(n + 1)p (n = 2 in Na, n = 3 in K, n = 4 in Rb, n = 5 in Cs) configurations of alkali atoms ions from LS-coupling to jK-coupling has been studied by comparing the experimental photoelectron spectra with the results obtained with analytical LS-coupling and jK-coupling models.

  • 46.
    Mårtensson, Nils
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Sokolowski, Evelyn
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    50 years anniversary of the discovery of the core level chemical shifts. The early years of photoelectron spectroscopy2014In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 193, p. 27-33Article in journal (Refereed)
    Abstract [en]

    The pioneering years of photoelectron spectroscopy in Uppsala are discussed, especially the work leading to the discovery of the core level chemical shifts. At a very early stage of the project, the pioneering group observed what they described as evidence for chemical shifts in the core level binding energies. However, it can now be seen that the initial observations to a large extent was due to charging of the samples. It is interesting to note that the decisive experiment was realized, not as a result of a systematic study, but was obtained with a large element of serendipity. Only when a chemical binding energy shift was observed between two S2p electron lines in the same molecule, the results were accepted internationally, and the fascinating expansion of modern core level photoelectron spectroscopy could start.

  • 47.
    Nordgren, Joseph
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Resonant soft X-ray emission for studies of molecules and solids2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 188, no SI, p. 3-9Article in journal (Refereed)
    Abstract [en]

    Resonant inelastic X-ray scattering (RIXS) has emerged as a powerful method for the study of the electronic structure of matter in various phases and ambient conditions. The selectivity offered by resonant excitation and polarization control in RIXS experiments offers rich information on excitations in molecules, liquids, and solids. The photon-in photon-out nature of RIXS makes it an interesting method in the study of ultra-high brightness FEL radiation interaction with matter. The present work offers an introductory review on the sub-key RIXS, including some historic comments.

  • 48. Olovsson, Weine
    et al.
    Marten, Tobias
    Holmström, Erik
    Johansson, Börje
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Abrikosov, Igor A.
    First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 178, p. 88-99Article in journal (Refereed)
    Abstract [en]

    We present a brief overview of recent theoretical studies of the core-level binding energy shift (CLS) in solid metallic materials. The focus is on first principles calculations using the complete screening picture, which incorporates the initial (ground state) and final (core-ionized) state contributions of the electron photoemission process in X-ray photoelectron spectroscopy (XPS), all within density functional theory (DFT). Considering substitutionally disordered binary alloys, we demonstrate that on the one hand CLS depend on average conditions, such as volume and overall composition, while on the other hand they are sensitive to the specific local atomic environment. The possibility of employing layer resolved shifts as a tool for characterizing interface quality in fully embedded thin films is also discussed, with examples for CuNi systems. An extension of the complete screening picture to core-core-core Auger transitions is given, and new results for the influence of local environment effects on Auger kinetic energy shifts in fcc AgPd are presented.

  • 49.
    Ottosson, Niklas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Faubel, Manfred
    Bradforth, Stephen E.
    Jungwirth, Pavel
    Winter, Bernd
    Photoelectron spectroscopy of liquid water and aqueous solution: Electron effective attenuation lengths and emission-angle anisotropy2010In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 177, no 2-3, p. 60-70Article in journal (Refereed)
    Abstract [en]

    Photoelectron (PE) spectroscopy measurements from liquid water and from a 4m NaI aqueous solution are performed using a liquid microjet in combination with soft X-ray synchrotron radiation. From the oxygen is PE signal intensity from liquid water, measured as a function of photon energy (up to 1500 eV), we quantitatively determine relative electron inelastic effective attenuation lengths (EAL) for (photo)electron kinetic energies in the 70-900 eV range. In order to determine the absolute electron escape depths a calibration point is needed, which is not directly accessible by experiment. This information can instead be indirectly derived by comparing PE experiments and molecular dynamics (MD) simulations of an aqueous solution interface where density profiles of water, anions, and cations are distinctively different. We have chosen sodium iodide in water because iodide has a considerable propensity for the solution surface, whereas the sodium cation is repelled from the surface. By measuring the intensities of photoelectrons emitted from different orbitals of different symmetries from each aqueous ion we also evaluate whether gas-phase ionization cross sections and asymmetry parameters can describe the photoemission from ions at and near the aqueous solution/vapor interface. We show that gas-phase data reproduce surprisingly well the experimental observations for hydrated ions as long as the photon energy is sufficiently far above the ionization threshold. Electrons detected at the higher photon energies originate predominantly from deeper layers, suggesting that bulk-solution electron elastic scattering is relatively weak.

  • 50. Ovsyannikov, R.
    et al.
    Karlsson, P.
    Lundqvist, M.
    Lupulescu, C.
    Eberhardt, W.
    Foehlisch, A.
    Svensson, Svante
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mårtensson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Principles and operation of a new type of electron spectrometer - ArTOF2013In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 191, p. 92-103Article in journal (Refereed)
    Abstract [en]

    A new energy and angular electron analyzer ArTOF (Angular Resolved Time of Flight) is described. The analyzer is based on simultaneous measurement of flight times and angles in an advanced electron lens system. In angular modes the new analyzer combines an increase in transmission by almost three orders of magnitude with improved resolution, in comparison to standard state-of-the-art electron spectrometers. In this report we describe some design principles and we give a review of calibration and alignment procedures necessary for the use of the ArTOF on a synchrotron radiation facility. Our program scripts to handle the large datasets are also discussed. Furthermore we give a broad description of the new research fields that benefit from the use of the ArTOF and give a short summary of the first results of angle resolved photoemission measurement with ArTOF using the single-bunch X-ray pulses from the BESSY II storage ring facility.

12 1 - 50 of 77
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