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  • 1. Alagia, M
    et al.
    Richter, R
    Stranges, S
    Agåker, Marcus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Ström, Magnus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Söderström, Johan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Såthe, Conny
    Department of Physics and Materials Science, Physics II.
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Sorensen, Stacey
    de Fanis, A
    Ueda, K
    Fink, R
    Rubensson, Jan-Erik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Core level ionization dynamics in small molecules studied by x-ray-emission threshold-electron coincidence spectroscopy2005In: Physical Review A, Vol. 71, no 1Article in journal (Refereed)
  • 2. Andersson, E.
    et al.
    Linusson, P.
    Fritzsche, S.
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Formation of Kr3+ via core-valence doubly ionized intermediate states2012In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 85, no 3, p. 032502-Article in journal (Refereed)
    Abstract [en]

    The time-of-flight photoelectron-photoion coincidence technique has been used to study single-photon 3d(9)4p(5) core-valence double ionization of Kr and subsequent Auger decay to triply charged states associated with the 4s(2)4p(3) and 4s(1)4p(4) configurations. The photon energy used was h nu = 150 eV. Multiconfiguration Dirac-Fock calculations were performed both for the doubly ionized intermediate states and the triply ionized final states. The intermediate states of Kr2+ are observed between 120 and 125 eV, whereas the final states of Kr3+ are observed between 74- and 120-eV ionization energy. Assignments of all structures are made based on the present numerical results. The calculated Auger rates give a detailed explanation of the relative line strengths observed.

  • 3.
    Andersson, Egil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Fritzsche, Stephan
    Linusson, Per
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Eland, John H. D.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Multielectron coincidence study of the double Auger decay of 3d-ionized krypton2010In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 82, no 4, p. 043418-Article in journal (Refereed)
    Abstract [en]

    Multielectron coincidence data for triple ionization of krypton have been recorded above the 3d ionization threshold at two photon energies (140 and 150 eV). Three principal transition pathways have been observed, two involving double Auger transitions from Kr+, and one involving single Auger transitions from Kr2+ created by direct single-photon double ionization. The decay of the 3d(9) D-2(5/2,3/2) states in Kr+ has been analyzed in some detail and is found to be strongly dominated by cascade processes where two electrons with well-defined energies are emitted. The decay paths leading to the 4s(2)4p(3) S-4, D-2, and P-2 states of Kr3+ are analyzed and energies of seven intermediate states in Kr2+ are given. A preliminary investigation of the decay paths from Kr+ 3d (9)4p(5)nl shake-up states has also been carried out.

  • 4.
    Andersson, Egil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Niskanen, Johannes
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Linusson, Per
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Carravetta, V.
    Ågren, Hans
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Core-valence double photoionization of the CS2 molecule2010In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 133, no 9, p. 094305-Article in journal (Refereed)
    Abstract [en]

    Double photoionization spectra of the CS2 molecule have been recorded using the TOF-PEPECO technique in combination with synchrotron radiation at the photon energies h nu=220, 230, 240, 243, and 362.7 eV. The spectra were recorded in the S 2p and C 1s inner-shell ionization regions and reflect dicationic states formed out of one inner-shell vacancy and one vacancy in the valence region. MCSCF calculations were performed to model the energies of the dicationic states. The spectra associated with a S 2p vacancy are well structured and have been interpreted in some detail by comparison to conventional S 2p and valence photoelectron spectra. The lowest inner-shell-valence dicationic state is observed at the vertical double ionization energy 188.45 eV and is associated with a (2p(3/2))(-1)(2 pi(g))(-1) double vacancy. The spectrum connected to the C 1s vacancy shows a distinct line at 310.8 eV, accompanied by additional broad features at higher double ionization energies. This line is associated with a (C 1s)(-1)(2 pi(g))(-1) double vacancy.

  • 5. Berrah, Nora
    et al.
    Fang, Li
    Murphy, Brendan
    Osipov, Timur
    Ueda, Kiyoshi
    Kukk, Edwin
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    van der Meulen, Peter
    Salen, Peter
    Schmidt, Henning T.
    Thomas, Richard D.
    Larsson, Mats
    Richter, Robert
    Prince, Kevin C.
    Bozek, John D.
    Bostedt, Christoph
    Wada, Shin-ichi
    Piancastelli, Maria N.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Tashiro, Motomichi
    Ehara, Masahiro
    Double-core-hole spectroscopy for chemical analysis with an intense X-ray femtosecond laser2011In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 41, p. 16912-16915Article in journal (Refereed)
    Abstract [en]

    Theory predicts that double-core-hole (DCH) spectroscopy can provide a new powerful means of differentiating between similar chemical systems with a sensitivity not hitherto possible. Although DCH ionization on a single site in molecules was recently measured with double-and single-photon absorption, double-core holes with single vacancies on two different sites, allowing unambiguous chemical analysis, have remained elusive. Here we report that direct observation of double-core holes with single vacancies on two different sites produced via sequential two-photon absorption, using short, intense X-ray pulses from the Linac Coherent Light Source free-electron laser and compare it with theoretical modeling. The observation of DCH states, which exhibit a unique signature, and agreement with theory proves the feasibility of the method. Our findings exploit the ultrashort pulse duration of the free-electron laser to eject two core electrons on a time scale comparable to that of Auger decay and demonstrate possible future X-ray control of physical inner-shell processes.

  • 6.
    Burmeister, Florian
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Andersson, L M
    Department of Quantum Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Richter, T
    Zimmerman, P
    Godehusen, K
    Karlsson, Hans
    Department of Quantum Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Sorensen, S L
    Björneholm, Olle
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Wiesner, Karoline
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Goscinski, Osvaldo
    Department of Quantum Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V.
    A study of the inner-valence ionization region in HCl and DCl2004In: Journal of Physics B: At. Mol. Opt. Phys., Vol. 37, p. 1173-Article in journal (Refereed)
  • 7. Eland, J H D
    et al.
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Double ionisation of ICN and BrCN studied by a new photoelectron-photoion coincidence technique2006In: Chemical Physics, Vol. 327, no 1, p. 85-90Article in journal (Refereed)
  • 8.
    Eland, John H. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Andric, L.
    Linusson, P.
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Plogmaker, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Palaudoux, J.
    Penent, F.
    Lablanquie, P.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Triple ionization of CO(2) by valence and inner shell photoionization2011In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 135, no 13, p. 134309-Article in journal (Refereed)
    Abstract [en]

    Spectra of triply ionized CO(2) have been obtained from photoionization of the molecule using soft x-ray synchrotron light and an efficient multi-electron coincidence technique. Although all states of the CO(2)(+++) trication are unstable, the ionization energy for formation of molecular ions at a geometry similar to that of the neutral molecule is determined as 74 +/- 0.5 eV.

  • 9.
    Eland, John H. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Linusson, P.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Homonuclear site-specific photochemistry by an ion-electron multi-coincidence spectroscopy technique2012In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 548, p. 90-94Article in journal (Refereed)
    Abstract [en]

    By combining multi-particle coincidence detection of electrons and ions with ionisation by soft X-ray synchrotron radiation we demonstrate an effective tool for atomic spectroscopy and site-specific photochemistry. Its most novel capability is application to molecular fragmentation after K-shell vacancy production in atoms distinguished only by their chemical environment.

  • 10.
    Eland, John H. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Zagorodskikh, Sergey
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Squibb, Richard J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Sorensen, S. L.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Carbon dioxide ion dissociations after inner shell excitation and ionization: The origin of site-specific effects2014In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 140, no 18, p. 184305-Article in journal (Refereed)
    Abstract [en]

    Multi-coincidence experiments with detection of both electrons and ions from decay of core-excited and core-ionized states of CO2 confirm that O-2(+) is formed specifically in Auger decay from the C1s-pi* and O1s-pi* resonances. Molecular rearrangement occurs by bending in the resonant states, and O-2(+) is produced by both single and double Auger decay. It is suggested that electron capture by C+ after partial dissociation in the doubly ionized core of excited CO2+, formed by shake-up in spectator resonant Auger decay, accounts for high kinetic energy and high internal energy in some C + O-2(+) fragments.

  • 11. Fang, L.
    et al.
    Osipov, T.
    Murphy, B.
    Juranic, P.
    Berrah, N.
    Kukk, E.
    Ueda, K.
    Feifel, R.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    van der Meulen, P.
    Salen, P.
    Schmidt, H.
    Thomas, R.
    Larsson, M.
    Richter, R.
    Prince, K. C.
    Bozek, J. D.
    Bostedt, C.
    Wada, S.
    Piancastelli, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Tashiro, M.
    Ehara, M.
    Tarantelli, F.
    Multiple Ionization and Double Core-hole Production in Molecules using the LCLS X-ray FEL2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 3, p. 032028-Article in journal (Refereed)
    Abstract [en]

    We used the world's first hard x-ray FEL to investigate the response of molecular systems to the ultra-intense, femtosecond x-ray radiation. We report sequential multiphoton ionization, frustrated absorption and double core hole production mechanisms.

  • 12. Farrell, J. P.
    et al.
    McFarland, B. K.
    Berrah, N.
    Bostedt, C.
    Bozek, J.
    Bucksbaum, P. H.
    Coffee, R.
    Cryan, J.
    Fang, L.
    Feifel, R.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Gaffney, K.
    Glownia, J.
    Martinez, T.
    Mucke, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Murphy, B.
    Miyabe, S.
    Natan, A.
    Osipov, T.
    Petrovic, V.
    Schorb, S.
    Schultz, T.
    Spector, L.
    Tarantelli, F.
    Tenney, I.
    Wang, S.
    White, W.
    White, J.
    Guehr, M.
    Ultrafast X-ray probe of nucleobase photoprotection2012In: Quantum Electronics and Laser Science Conference: Strong-Field and Short-Wavelength Interactions (QW1F), 2012, p. 6327153-Conference paper (Refereed)
    Abstract [en]

    We will present first results of a UV-pump X-ray-probe study of the photoprotection mechanism of thymine. The experiment used element specific Auger spectroscopy and was carried out at the LCLS.

  • 13.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Andersson, M.
    Öhrwall, Gunnar
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Sorensen, S. L.
    Piancastelli, Maria-Novella
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Björneholm, Olle
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    A quantitative analysis of the N 1s ­> p* photoabsorption profile in N2: new spectroscopic constants for the core-excited state2004In: Chemical Physics Letters, Vol. 383, no 3-4, p. 222-229Article in journal (Refereed)
  • 14.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Baev, A.
    Gelmukhanov, F.
    Ågren, H.
    Andersson, M.
    Öhrwall, Gunnar
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Piancastelli, Maria-Novella
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Miron, C.
    Sorensen, S. L.
    Naves de Brito, A.
    Björneholm, Olle
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Role of stray light in the formation of high-resolution resonant photoelectron spectra: An experimental an theoretical study2004In: Journal of Electron Spectroscopy Relat. Phenom., Vol. 134, no 1, p. 49-Article in journal (Refereed)
  • 15.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Baev, A.
    Gelmukhanov, Faris
    Ågren, Hans
    Piancastelli, Maria-Novella
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Andersson, M.
    Öhrwall, Gunnar
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Miron, C.
    Sorensen, S. L.
    Naves de Brito, A.
    Björneholm, Olle
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Generalization of the duration time concept for interpreting high resolution resonant photoemission spectra2004In: Physical Review A, Vol. 69, p. 022707-Article in journal (Refereed)
  • 16.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Vibrationally selected O+-O+ fragmentation of O-2 below the adiabatic double-ionization potential studied via electron-electron coincidence spectroscopy2006In: Physical Review A, Vol. 73, no 1Article in journal (Refereed)
  • 17.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Vibrationally selected O+-O+ fragmentation of O-2 below the adiabatic double-ionization potential studied via electron-electron coincidence spectroscopy2005In: Physical Review A, Vol. 71, no 3Article in journal (Refereed)
  • 18.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Edvardsson, David
    Valence double ionization of O-2 at photon energies below and above the molecular double ionization threshold2005In: Journal of Chemical Physics, Vol. 122, no 14Article in journal (Refereed)
  • 19.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Storchi, L
    Tarantelli, F
    An experimental and theoretical study of double photoionization of CF4 using time-of-flight photoelectron-photoelectron (photoion-photoion) coincidence spectroscopy2006In: Journal of Chemical Physics, Vol. 125, no 19Article in journal (Refereed)
  • 20.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Storchi, L
    Tarantelli, F
    Complete valence double photoionization of SF62005In: Journal of Chemical Physics, Vol. 122, no 14Article in journal (Refereed)
  • 21.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Gel´mukhanov, F
    Baev, A
    Ågren, H
    Piancastelli, Maria Novella
    Bässler, M
    Miron, C
    Sorensen, Stacey L
    Naves de Brito, Arnaldo
    Björneholm, Olle
    Karlsson, Leif
    Svensson, Svante
    Interference Quenching of v2002In: Physical Review Letters, Vol. 89, no 10, p. 103002-1Article in journal (Refereed)
  • 22.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics V.
    Karlsson, Leif
    Department of Physics and Materials Science, Physics V.
    Piancastelli, Maria Novella
    Department of Physics and Materials Science, Physics V.
    Fink, R F
    Bässler, M
    Björneholm, Olle
    Department of Physics and Materials Science, Physics V.
    Wiesner, Karoline
    Miron, C
    Wang, H
    Giertz, Annica
    Sorensen, Stacey L
    Naves de Brito, Arnaldo
    Svensson, Svante
    Department of Physics and Materials Science, Physics V.
    "Hidden" vibrations in CO: Reinvestigation of resonant Auger decay for the C 1s ->pi* excitation2002In: Physical Review A, Vol. 65, no 5, p. 052701-Article in journal (Refereed)
  • 23.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Kimberg, V.
    Baev, A.
    Gel´mukhanov, Faris
    Ågren, Hans
    Miron, C.
    Öhrwall, Gunnar
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Piancastelli, Maria Novella
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Sorensen, Stacey
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Profile of Resonant Photoelectron Spectra versus the Spectral Function Width and Photon Frequency Detuning2004In: Physical Review, Vol. 70, no 3, p. 032708-Article in journal (Refereed)
  • 24.
    Feifel, Raimund
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Tchaplyguine, Maxim
    Öhrwall, Gunnar
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Lundwall, Marcus
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Marinho, Ricardo
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Gisselbrecht, M.
    Sorensen, S. L.
    Naves de Brito, A.
    Karlsson, Leif
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Mårtensson, Nils
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Svensson, Svante
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    Björneholm, Olle
    Department of Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Physics V. Physics II.
    From localised to delocalised electronic states in free Ar, Kr and Xe clusters2004In: The European Physical Journal D, Vol. 30, no 3, p. 343-351Article in journal (Refereed)
  • 25. Frasinski, L. J.
    et al.
    Zhaunerchyk, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Squibb, Richard J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Siano, M.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Linusson, P.
    v. d. Meulen, P.
    Salen, P.
    Thomas, R. D.
    Larsson, M.
    Foucar, L.
    Ullrich, J.
    Motomura, K.
    Mondal, S.
    Ueda, K.
    Osipov, T.
    Fang, L.
    Murphy, B. F.
    Berrah, N.
    Bostedt, C.
    Bozek, J. D.
    Schorb, S.
    Messerschmidt, M.
    Glownia, J. M.
    Cryan, J. P.
    Coffee, R. N.
    Takahashi, O.
    Wada, S.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Richter, R.
    Prince, K. C.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Dynamics of Hollow Atom Formation in Intense X-Ray Pulses Probed by Partial Covariance Mapping2013In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 111, no 7, article id 073002Article in journal (Refereed)
    Abstract [en]

    When exposed to ultraintense x-radiation sources such as free electron lasers (FELs) the innermost electronic shell can efficiently be emptied, creating a transient hollow atom or molecule. Understanding the femtosecond dynamics of such systems is fundamental to achieving atomic resolution in flash diffraction imaging of noncrystallized complex biological samples. We demonstrate the capacity of a correlation method called "partial covariance mapping'' to probe the electron dynamics of neon atoms exposed to intense 8 fs pulses of 1062 eV photons. A complete picture of ionization processes competing in hollow atom formation and decay is visualized with unprecedented ease and the map reveals hitherto unobserved nonlinear sequences of photoionization and Auger events. The technique is particularly well suited to the high counting rate inherent in FEL experiments.

  • 26. Fukuzawa, H.
    et al.
    Son, S. -K
    Motomura, K.
    Mondal, S.
    Nagaya, K.
    Wada, S.
    Liu, X. -J
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Tachibana, T.
    Ito, Y.
    Kimura, M.
    Sakai, T.
    Matsunami, K.
    Hayashita, H.
    Kajikawa, J.
    Johnsson, P.
    Siano, M.
    Kukk, E.
    Rudek, B.
    Erk, B.
    Foucar, L.
    Robert, E.
    Miron, C.
    Tono, K.
    Inubushi, Y.
    Hatsui, T.
    Yabashi, M.
    Yao, M.
    Santra, R.
    Ueda, K.
    Deep Inner-Shell Multiphoton Ionization by Intense X-Ray Free-Electron Laser Pulses2013In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 110, no 17, article id 173005Article in journal (Refereed)
    Abstract [en]

    We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xen+ with n up to 26 is produced at a photon energy of 5.5 keV. The observed high charge states (n >= 24) are produced via five-photon absorption, evidencing the occurrence of multiphoton absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement with the experiment, elucidates the complex pathways of sequential electronic decay cascades accessible in heavy atoms. The present study of heavy-atom ionization dynamics in high-intensity hard-x-ray pulses makes a step forward towards molecular structure determination with x-ray free-electron lasers.

  • 27.
    Hedin, Lage
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Tashiro, M.
    Linusson, P.
    Eland, J. H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Ehara, M.
    Ueda, K.
    Zhaunerchyk, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Pernestål, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    N1s and O1s double ionization of the NO and N2O molecules2014In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 140, no 4, p. 044309-Article in journal (Refereed)
    Abstract [en]

    Single-site N1s and O1s double core ionisation of the NO and N2O molecules has been studied using a magnetic bottle many-electron coincidence time-of-flight spectrometer at photon energies of 1100 eV and 1300 eV. The double core hole energies obtained for NO are 904.8 eV (N1s(-2)) and 1179.4 eV (O1s(-2)). The corresponding energies obtained for N2O are 896.9 eV (terminal N1s(-2)), 906.5 eV (central N1s(-2)), and 1174.1 eV (O1s(-2)). The ratio between the double and single ionisation energies are in all cases close or equal to 2.20. Large chemical shifts are observed in some cases which suggest that reorganisation of the electrons upon the double ionization is significant. Delta-self-consistent field and complete active space self-consistent field (CASSCF) calculations were performed for both molecules and they are in good agreement with these results. Auger spectra of N2O, associated with the decay of the terminal and central N1s(-2) as well as with the O1s(-2) dicationic states, were extracted showing the two electrons emitted as a result of filling the double core holes. The spectra, which are interpreted using CASSCF and complete active space configuration interaction calculations, show atomic-like character. The cross section ratio between double and single core hole creation was estimated as 1.6 x 10(-3) for nitrogen at 1100 eV and as 1.3 x 10(-3) for oxygen at 1300 eV. (C) 2014 AIP Publishing LLC.

  • 28.
    Hedin, Lage
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Tashiro, M.
    Linusson, P.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Ehara, M.
    Ueda, K.
    Zhaunerchyk, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Single site double core level ionisation of OCS2014In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 439, p. 111-116Article in journal (Refereed)
    Abstract [en]

    Single site O1s, C1s and S2p double ionisation of the OCS molecule has been investigated using a magnetic bottle multi-electron coincidence time-of-flight spectrometer. Photon energies of 1300, 750 and 520 eV, respectively, were used for the ionisation, and spectra were obtained from which the double core ionisation energies could be determined. The energies measured for 1s double ionisation are 1172 eV (O1s(-2)) and 659 eV (C1s(-2)). For the S2p double ionisation three dicationic states are expected, P-3, D-1 and S-1. The ionisation energies obtained for these states are 373 eV (P-3), 380 eV (D-1) and 388 eV (S-1). The ratio between the double and single core ionisation energies are in all cases equal or close to 2.20. Auger spectra of OCS, associated with the O1s(-2), C1s(-2) and S2p(-2) dicationic states, were also recorded incorporating both electrons emitted as a result of the filling of the two core vacancies. As for other small molecules, the spectra show an atomic-like character with Auger bands located in the range 480-560 eV for oxygen, 235-295 eV for carbon and 100-160 eV for sulphur. The interpretation of the spectra is supported by CASSCF and CASCI calculations. The cross section ratio between double and single core hole creation was estimated as 3.7 x 10(-4) for oxygen at 1300 eV, 3.7 x 10(-4) for carbon at 750 eV and as 2.2 x 10(-3) for sulphur at 520 eV. 

  • 29. Holland, D M P
    et al.
    Potts, A W
    Trofimov, A B
    Breidbach, J
    Schirmer, J
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Richter, T
    Godehusen, K
    Martins, M
    Tutay, A
    Yalcinkaya, M
    Al-Hada, M
    Eriksson, S
    Karlsson, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    An experimental and theoretical study of the valence shell photoelectron spectrum of tetrafluoromethane2005In: Chemical Physics, Vol. 308, no 1-2, p. 43-57Article in journal (Refereed)
  • 30. Kottirsch, G
    et al.
    Koch, G
    Feifel, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II. Fysik II.
    beta-aryl-suceinic acid hydroxamates as dual inhibitors of matrix metalloproteinases and tumor necrosis factor alpha converting enzyme2002In: Journal of Medicinal Chemistry, Vol. 45, no 11, p. 2289-2293Article in journal (Refereed)
  • 31. Larsson, M.
    et al.
    Salen, P.
    van der Meulen, P.
    Schmidt, H. T.
    Thomas, R. D.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Piancastelli, Maria Novella
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Fang, L.
    Murphy, B. F.
    Osipov, T.
    Berrah, N.
    Kukk, E.
    Ueda, K.
    Bozek, J. D.
    Bostedt, C.
    Wada, S.
    Richter, R.
    Feyer, V.
    Prince, K. C.
    Double core-hole formation in small molecules at the LCLS free electron laser2013In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 46, no 16 SI, article id 164030Article in journal (Refereed)
    Abstract [en]

    We have investigated nonlinear processes in small molecules by x-ray photoelectron spectroscopy using the Linac Coherent Light Source free electron laser, and by simulations. The main focus of the experiments was the formation of the two-site double core-hole (tsDCH) states in the molecules CO2, N2O and N-2. These experiments are described in detail and the results are compared with simulations of the photoelectron spectra. The double core-hole states, and in particular the tsDCH states, have been predicted to be highly sensitive to the chemical environment. The theory behind this chemical sensitivity is validated by the experiments. Furthermore, our simulations of the relative integrated intensities of the peaks associated with the nonlinear processes show that this type of simulation, in combination with experimental data, provides a useful tool for estimating the duration of ultra-short x-ray pulses.

  • 32. Linusson, P.
    et al.
    Fritzsche, S.
    Eland, J. H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Single-photon multiple ionization forming double vacancies in the 2p subshell of argon2013In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, no 4, article id 043409Article in journal (Refereed)
    Abstract [en]

    Single-photon ionization leading to two vacancies in the 2p subshell of argon is investigated experimentally using the photoelectron time-of-flight magnetic bottle coincidence technique. Three peaks corresponding to the P-3, D-1, and S-1 states of the dication are found in the ionization energy range 535 to 562 eV. Multiconfigurational Dirac-Fock calculations were performed to estimate the single-photon double-ionization cross sections. Reasonable agreement between the measured and simulated spectra is found if single and double excitations are taken into account in the wave-function expansion. 

  • 33. Linusson, P.
    et al.
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Squibb, Richard J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Zagorodskikh, Sergey
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Complete double valence photoionization study of the electron spectra of krypton2013In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 88, no 2, article id 022510Article in journal (Refereed)
    Abstract [en]

    Double photoionization spectra of Kr have been recorded using monochromatized synchrotron radiation of 88 eV photon energy and a versatile multielectron coincidence time-of-flight spectroscopy technique. The formation of the Kr2+ states of the lowest-energy configuration 4s(2)4p(4) is partly direct, producing electron pairs with a continuous distribution, and partly indirect via superexcited singly ionized states. The superexcited Kr+ states show strong and hitherto unexplained selectivity in branching to final Kr2+ states. Kr2+ states based on excited configurations are formed mainly by direct double photoionization.

  • 34. Machado Bueno, André
    et al.
    Naves de Brito, Arnaldo
    Fink, Reinhold F.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Bässler, Margit
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Björneholm, Olle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Burmeister, Florian
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Miron, Catalin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Sorensen, Stacey L.
    Wang, Honghong
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Svensson, Svante
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics.
    Influence of chemical bonds on the lifetime of the molecular-field-split 2p levels in H2S2003In: Phys. Rev. A, Vol. 67, p. 22714:1-7Article in journal (Refereed)
  • 35. McFarland, B. K.
    et al.
    Farrell, J. P.
    Miyabe, S.
    Tarantelli, F.
    Aguilar, A.
    Berrah, N.
    Bostedt, C.
    Bozek, J. D.
    Bucksbaum, P. H.
    Castagna, J. C.
    Coffee, R. N.
    Cryan, J. P.
    Fang, L.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gaffney, K. J.
    Glownia, J. M.
    Martinez, T. J.
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Murphy, B.
    Natan, A.
    Osipov, T.
    Petrovic, V. S.
    Schorb, S.
    Schultz, Th.
    Spector, L. S.
    Swiggers, M.
    Tenney, I.
    Wang, S.
    White, J. L.
    White, W.
    Guehr, M.
    Ultrafast X-ray Auger probing of photoexcited molecular dynamics2014In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 5, p. 4235-Article in journal (Refereed)
    Abstract [en]

    Molecules can efficiently and selectively convert light energy into other degrees of freedom. Disentangling the underlying ultrafast motion of electrons and nuclei of the photoexcited molecule presents a challenge to current spectroscopic approaches. Here we explore the photoexcited dynamics of molecules by an interaction with an ultrafast X-ray pulse creating a highly localized core hole that decays via Auger emission. We discover that the Auger spectrum as a function of photoexcitation-X-ray-probe delay contains valuable information about the nuclear and electronic degrees of freedom from an element-specific point of view. For the nucleobase thymine, the oxygen Auger spectrum shifts towards high kinetic energies, resulting from a particular C-O bond stretch in the pi pi* photoexcited state. A subsequent shift of the Auger spectrum towards lower kinetic energies displays the electronic relaxation of the initial photoexcited state within 200 fs. Ab-initio simulations reinforce our interpretation and indicate an electronic decay to the n pi* state.

  • 36. McFarland, B.K.
    et al.
    Berrah, N.
    Bostedt, C.
    Bozek, J.
    Bucksbaum, P.H.
    Castagna, J.C.
    Coffee, R.N.
    Cryan, J.P.
    Fang, L.
    Farrell, J.P.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gaffney, K.J.
    Glownia, J.M.
    Martinez, T.J.
    Miyabe, S.
    Mucke, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Murphy, B.
    Natan, A.
    Osipov, T.
    Petrovic, V.S.
    Schorb, S.
    Schultz, Th.
    Spector, L.S.
    Swiggers, M.
    Tarantelli, F.
    Tenney, I.
    Wang, S.
    White, J.L.
    White, W.
    Gühr, M.
    Experimental strategies for optical pump - soft x-ray probe experiments at the LCLS2014In: Journal of Physics: Conference Series, Vol. 488, p. 012015-Article in journal (Refereed)
  • 37. Motomura, K.
    et al.
    Fukuzawa, H.
    Son, S-K
    Mondal, S.
    Tachibana, T.
    Ito, Y.
    Kimura, M.
    Nagaya, K.
    Sakai, T.
    Matsunami, K.
    Wada, S.
    Hayashita, H.
    Kajikawa, J.
    Liu, X-J
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Johnsson, P.
    Siano, M.
    Kukk, E.
    Rudek, B.
    Erk, B.
    Foucar, L.
    Robert, E.
    Miron, C.
    Tono, K.
    Inubushi, Y.
    Hatsui, T.
    Yabashi, M.
    Yao, M.
    Santra, R.
    Ueda, K.
    Sequential multiphoton multiple ionization of atomic argon and xenon irradiated by X-ray free-electron laser pulses from SACLA2013In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 46, no 16 SI, article id 164024Article in journal (Refereed)
    Abstract [en]

    We have investigated multiphoton multiple ionization of argon and xenon atoms at 5 keV using a new x-ray free electron laser (XFEL) facility, the SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan. The experimental results are compared with the new theoretical results presented here. The absolute fluence of the XFEL pulse has been determined with the help of the calculations utilizing two-photon processes in the argon atom. The high charge states up to +22 observed for Xe in comparison with the calculations point to the occurrence of sequential L-shell multiphoton absorption and of resonance-enabled x-ray multiple ionization.

  • 38.
    Mucke, Melanie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Takahashi, O.
    Linusson, P.
    Lebrun, Delphine
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Ueda, K.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Formation and decay of core-orbital vacancies in the water molecule2013In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 558, p. 82-87Article in journal (Refereed)
    Abstract [en]

    Primary steps in the interaction of high energy photons with water creating multiply ionised products are examined experimentally and theoretically. Double Auger decay from a 1s-hole state populates triply ionised states between 80 and 140 eV binding energy. Ejection of one 1s electron and one valence electron gives states around 570 eV which decay to triply ionised states between 75 and 110 eV. Nuclear motion in these states competes with Auger decay and substantially modifies the final state spectra. The double core-hole state from ionisation of both 1s electrons is found at 1171 +/- 1 eV and calculated at 1170.85 eV. 

  • 39. Nagaya, K.
    et al.
    Iwayama, H.
    Yase, S.
    Sugishima, A.
    Mizoguchi, Y.
    Yao, M.
    Fukuzawa, H.
    Motomura, K.
    Yamada, A.
    Wang, C.
    Liu, X. -J
    Ueda, K.
    Saito, N.
    Rudenko, A.
    Faucer, L.
    Kurka, M.
    Kuhnel, K. -U
    Ullrich, J.
    Czasch, A.
    Dorner, R.
    Feilfel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Piseri, P.
    Mazza, T.
    Devetta, M.
    Coreno, M.
    Belkacem, A.
    Nagasono, M.
    Higashiya, A.
    Tono, K.
    Yabashi, M.
    Ishikawa, T.
    Ohashi, H.
    Kimura, H.
    Togashi, T.
    Senba, Y.
    Multiple photoionization of rare-gas clusters by EUV-FEL at Spring-82012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 3, p. 032082-Article in journal (Refereed)
    Abstract [en]

    Multiple photoionization processes of giant rare-gas clusters are investigated in the wavelength region of 51 to 61nm at Spring8. We report here some latest results of our investigation; the frustration of photoionization for giant xenon clusters and the charge transfer in Ar-core Ne-shell clusters.

  • 40. Nagaya, K.
    et al.
    Sugishima, A.
    Iwayama, H.
    Murakami, H.
    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 University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Nagasono, M.
    Higashiya, A.
    Yabashi, M.
    Ishikawa, T.
    Togashi, T.
    Kimura, H.
    Ohashi, H.
    Unusual under-threshold ionization of neon clusters studied by ion spectroscopy2013In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 46, no 16 SI, article id 164023Article in journal (Refereed)
    Abstract [en]

    We carried out time-of-flight mass spectrometry for neon clusters that were exposed to intense free electron laser pulses with the wavelength of 62 nm, which induce optical transition from the ground state (2s(2) 2p(6)) to an excited state (2s(2) 2p(5) nl) in the Ne atoms. In contrast to Ne+ ions produced by two-photon absorption from isolated Ne atoms, the Ne+ ion yield from Ne clusters shows a linear dependence on the laser intensity (I). We discuss the ionization mechanisms which give the linear behaviour with respect to I and expected features in the electron emission spectrum.

  • 41. Niskanen, J.
    et al.
    Andersson, E.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Linusson, P.
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Vahtras, O.
    Symmetry breaking in core-valence double photoionization of SO22012In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 85, no 2, p. 023408-Article in journal (Refereed)
    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.

  • 42. Penent, F
    et al.
    Palaudoux, J
    Lablanquie, P
    Andric, L
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics II.
    Eland, J H D
    Multielectron spectroscopy: The xenon 4d hole double Auger decay2005In: Physical Review Letters, Vol. 95, no 8Article in journal (Refereed)
  • 43.
    Plogmaker, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Linusson, Per
    Eland, John H D
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Baker, Neville
    Johansson, Erik M J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Siegbahn, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region2012In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 83, no 1, p. 013115-Article in journal (Refereed)
    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.

  • 44. Saleacuten, P.
    et al.
    van der Meulen, P.
    Thomas, R. D.
    Schmidt, H. T.
    Larsson, M.
    Feifel, R.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Piancastelli, M. N.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Surface and Interface Science.
    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 Molecules2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 2, p. 022083-Article in journal (Refereed)
    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.

  • 45. Salen, P.
    et al.
    van der Meulen, P.
    Schmidt, H. T.
    Thomas, R. D.
    Larsson, M.
    Feifel, Raimund
    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.
    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 Laser2012In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 108, no 15, p. 153003-Article in journal (Refereed)
    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.

  • 46. Salen, Peter
    et al.
    Kaminska, Magdalena
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Squibb, Richard J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Richter, Robert
    Alagia, Michele
    Stranges, Stefano
    van der Meulen, Peter
    Eland, John H. D.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Zhaunerchyk, Vitali
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Selectivity in fragmentation of N-methylacetamide after resonant K-shell excitation2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 29, p. 15231-15240Article in journal (Refereed)
    Abstract [en]

    The fragmentation pattern of the peptide model system, N-methylacetamide, is investigated using ion time-of-flight (TOF) spectroscopy after resonant K-shell excitation. Corresponding near-edge X-ray absorption fine structure (NEXAFS) spectra recorded at high resolution at the C1s, N1s and O1s edges are presented. Analysis of the ion TOF data reveals a multitude of fragmentation channels and dissociation pathways. Comparison between the excitation of six different resonances in the vicinity of the C1s, N1s and O1s edges suggests evidence for site-selective bond breaking. In particular the breaking of the peptide bond and the N-C-alpha bond show a clear correlation with resonant excitation at the N1s edge. Also, stronger tendencies towards site-selective bond breaking are found for the generation of single ions compared with ion pairs. Analysis of angular distributions of ions from breakage of the peptide bond yields a fragmentation time of <400 fs.

  • 47. Schalk, Oliver
    et al.
    Schuurman, Michael S.
    Wu, Guorong
    Lang, Peter
    Mucke, Melanie
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Stolow, Albert
    Internal Conversion versus Intersystem Crossing: What Drives the Gas Phase Dynamics of Cyclic alpha,beta-Enones?2014In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 118, no 12, p. 2279-2287Article in journal (Refereed)
    Abstract [en]

    We investigate the competition between intersystem crossing (ISC) and internal conversion (IC) as nonradiative relaxation pathways in cyclic alpha,beta-unsaturated enones following excitation to their lowest lying (1)pi pi* state, by means of time-resolved photoelectron spectroscopy and ab initio computation. Upon excitation, the (1)pi pi* state of 2-cyclopentenone decays to the lowest lying (1)pi pi* state within 120 +/- 20 fs. Within 1.2 +/- 0.2 ps, the molecule subsequently decays to the triplet manifold and the singlet ground state, with quantum yields of 0.35 and 0.65, respectively. The corresponding dynamics in modified derivatives, obtained by selective methylation, show a decrease in both IC and ISC rates, with the quantum yields of ISC varying between 0.35 and 0.08. The rapid rates of ISC are explained by a large spin orbit coupling of 45-60 cm(-1) over an extended region of near degeneracy between the singlet and triplet state. Furthermore, the rate of IC is depressed by the existence of a well-defined minimum on the (1)n pi* potential energy surface. The nonadiabatic pathways evinced by the present results highlight the fact that these molecular systems conceptually represent "intermediate cases" between ultrafast dynamics mediated by vibrational motions at conical intersections versus those by statistical decay mechanisms.

  • 48. Sheinerman, S.
    et al.
    Linusson, P.
    Eland, John H. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Hedin, Lage
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Andersson, E.
    Rubensson, Jan-Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Karlsson, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Feifel, Raimund
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Influence of double Auger decay on low-energy 3d photoelectrons of krypton2012In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, no 2, p. 022515-Article in journal (Refereed)
    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.

  • 49. Sorensen, S.
    et al.
    Tanaka, T.
    Feifel, Raimund
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics V. Physics II.
    Eland, J. H. D.
    Kitajima, M.
    Tanaka, H.
    Sankari, R.
    De Fanis, A.
    Piancastelli, Maria Novella
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics V. Physics II.
    Karlsson, Leif
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Physics and Materials Science, Physics V. Physics II.
    Ueda, K.
    Application of an Atomic Relaxation Model for the Interpretation of O1s to Rydberg Excited Auger Electron Spectra of Molecular Oxygen2004In: Chemical Physics Letters, Vol. 398, no 1-3, p. 168-174Article in journal (Refereed)
  • 50. 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 University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    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 nm2012In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, no 3, p. 033203-Article in journal (Refereed)
    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.

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