| 1. |
- Schulz, M., et al.
(författare)
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Strongly Enhanced Backward Emission of Electrons in Transfer and Ionization
- 2012
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 108:4, s. 043202-
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Tidskriftsartikel (refereegranskat)abstract
- We studied three-dimensional angular distributions and longitudinal momentum spectra of electrons ejected in transfer plus ionization (TI), i.e., the ejection of one and the capture of a second target electron, for ion-helium collisions. We observe a pronounced structure strongly focused opposite to the projectile beam direction, which we associate with a new correlated TI mechanism proposed recently. This process contributes significantly to the total cross sections over a broad range of perturbations eta, even at eta as large as 0.5, where uncorrelated TI mechanisms were thought to be dominant.
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| 2. |
- Kaiser, L., et al.
(författare)
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Angular emission distribution of O 1s photoelectrons of uniaxially oriented methanol
- 2020
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 53:19
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Tidskriftsartikel (refereegranskat)abstract
- The angular distribution of O 1s photoelectrons emitted from uniaxially oriented methanol is studied experimentally and theoretically. We employed circularly polarized photons of an energy ofh nu= 550 eV for our investigations. We measured the three-dimensional photoelectron angular distributions of methanol, with the CH3-OH axis oriented in the polarization plane, by means of cold target recoil ion momentum spectroscopy. The experimental results are interpreted by single active electron calculations performed with the single center method. A comparative theoretical study of the respective molecular-frame angular distributions of O 1s photoelectrons of CO, performed for the same photoelectron kinetic energy and for a set of different internuclear distances, allows for disentangling the role of internuclear distance and the hydrogen atoms of methanol as compared to carbon monoxide.
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| 3. |
- Moshammer, R., et al.
(författare)
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Few-photon multiple ionization of Ne and Ar by strong free-electron-laser pulses
- 2007
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:20, s. 203001-
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Tidskriftsartikel (refereegranskat)abstract
- Few-photon multiple ionization of Ne and Ar atoms by strong vacuum ultraviolet laser pulses from the free-electron laser at Hamburg was investigated differentially with the Heidelberg reaction microscope. The light-intensity dependence of Ne2+ production reveals the dominance of nonsequential two-photon double ionization at intensities of I < 6x10(12) W/cm(2) and significant contributions of three-photon ionization as I increases. Ne2+ recoil-ion-momentum distributions suggest that two electrons absorbing "instantaneously" two photons are ejected most likely into opposite hemispheres with similar energies.
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| 4. |
- Gudmundsson, Magnus, et al.
(författare)
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Angular scattering in fast ion-atom electron transfer collisions : projectile wave diffraction and Thomas mechanisms
- 2010
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 43:18, s. 185209-
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Tidskriftsartikel (refereegranskat)abstract
- We report experimental angular differential cross sections for double-electron capture in He2+ + He collisions and single-electron capture in H+ + He collisions for the 1.3-12.5 MeV kinetic energy range. In all cases, the total cross sections are dominated by forward scattering peaks in d sigma/d Omega. The shapes and widths (but not the magnitudes) of these peaks are very similar for all energies and for capture of one or two electrons corresponding also to our measured linear increases in the transverse momentum transfers with increasing projectile velocities. These observations may be ascribed to diffraction limitations which are connected to electron transfer probabilities P(b) which are significant in limited regions of b only. For the H+ + He single-electron capture we observe two additional maxima in the angular differential cross sections. We conclude that while the secondary maxima at similar to 0.5 mrad probably have large contributions from the Thomas proton-electron-nucleus scattering mechanism, the third maxima at similar to 0.75 mrad are most likely mainly due to projectile de Broglie wave diffraction.
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| 5. |
- Schoeffler, Nicolas, et al.
(författare)
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Groundwater quality in the surroundings of Mafraq landfill, Jordan
- 2012
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Ingår i: Vatten: tidskrift för vattenvård /Journal of Water Management and research. - 0042-2886. ; 69
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Syftet med denna studie var dels att samla information om den sanitära status som gäller för Mafraqs deponi och dels att bedöma lakvattnets och grundvattnets kvalitet i dess närområde. Mafraqs deponi befinner sig på en av Jordaniens viktigaste akvifer och utgör därigenom ett potentielt hot mot grundvattnets kvalitet. I området runt om deponin används grundvattnet som dricksvatten och för konstbevattning, dess kvalitet var därför jämfört med standardvärden inom dessa användningsområden. Följande slutsatser drogs i samband med studien. Mafraqs deponi uppfyller inte de krav för att kvalificeras som sanitär. Lakvattnet är i direkt kontakt med grundvattnet under deponin och dess analys tyder på att förorening äger rum. Grundvattnet från flera brunnar hade för höga kvicksilver och fluor halter vilket gör dessa skadliga för männsikohälsan och därigenom olämpliga som dricksvatten. Grundvattnet från närmast alla brunnar visade sig inte vara fullt lämpliga om använt för konstbevattning på grund av dess för växter toxiska salthalter och natriumhalter. Konstbevattning med detta vatten medför speciell omtanke för val av grödor och bevattning skötsel om full avkastningspotential skall uppnås.
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| 6. |
- Ueda, Kiyoshi, et al.
(författare)
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Roadmap on photonic, electronic and atomic collision physics : I. Light-matter interaction
- 2019
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Ingår i: Journal of Physics B. - : IOP PUBLISHING LTD. - 0953-4075 .- 1361-6455. ; 52:17
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Tidskriftsartikel (refereegranskat)abstract
- We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light-matter interaction. In this area, studies of ultrafast electronic and molecular dynamics have been rapidly growing, with the advent of new light sources such as attosecond lasers and x-ray free electron lasers. In parallel, experiments with established synchrotron radiation sources and femtosecond lasers using cutting-edge detection schemes are revealing new scientific insights that have never been exploited. Relevant theories are also being rapidly developed. Target samples for photon-impact experiments are expanding from atoms and small molecules to complex systems such as biomolecules, fullerene, clusters and solids. This Roadmap aims to look back along the road, explaining the development of these fields, and look forward, collecting contributions from twenty leading groups from the field.
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