Sökning: "X-ray Absorption"

Visar resultat 6 - 10 av 314 avhandlingar innehållade orden X-ray Absorption.

  1. 6. X-ray scattering and spectroscopy of supercooled water and ice

    Författare :Jonas A. Sellberg; Anders Nilsson; Lars G. M. Pettersson; Thomas Loerting; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supercooled water; ice; x-ray scattering; x-ray spectroscopy; free-electron laser; kemisk fysik; Chemical Physics;

    Sammanfattning : This thesis presents experimental studies of water and ice at near-atmospheric pressures using intense x-rays only accessible at synchrotrons and free-electron lasers. In particular, it focuses on the deeply supercooled, metastable state and its implications on ice nucleation. LÄS MER

  3. 7. Resonant Soft X-Ray Emission Spectroscopy of Vanadium Oxides and Related Compounds

    Författare :Thorsten Schmitt; Joseph Nordgren; Laurent Duda; Stefan Eisebitt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; vanadium oxides; Li-battery; cathode materials; copper oxides; soft X-ray absorption; soft X-ray emission; resonant inelastic X-ray scattering; cluster model calculations; Fysik; Physics; Fysik;

    Sammanfattning : This thesis addresses the electronic structure of vanadium and copper oxides using soft X-ray absorption (SXA) spectroscopy and resonant inelastic X-ray scattering (RIXS) at high brightness synchrotron radiation sources. In RIXS incident photons, tuned to the energy of specific absorption resonances, are inelastically scattered leaving behind a low energy valence excitation in the system studied. LÄS MER

  4. 8. Laboratory X-Ray Phase-Contrast Imaging : Methods and Comparisons

    Författare :Tunhe Zhou; Anna Burvall; Hans M. Hertz; Tim Salditt; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray imaging; Phase-contrast; Liquid-metal-jet source; Propagation-based imaging; Grating-based imaging; Speckle-based imaging; Fysik; Physics;

    Sammanfattning : X-ray phase-contrast imaging has seen rapid development in recent decades due to its superior performance in imaging low-absorption objects, compared to traditional attenuation x-ray imaging. Having higher demand on coherence, x-ray phase-contrast imaging is performed mostly at synchrotrons. LÄS MER

  5. 9. X-ray spectroscopy on diatomic and cationic molecules

    Författare :Ludvig Kjellsson; Jan-Erik Rubensson; Marcus Agåker; Monica Turcato; Michael Meyer; John Bozek; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; resonant inelastic X-ray scattering; cationic molecule; dinitrogen; dioxygen; carbon monoxide; aqueous hydroxyl radical; lifetime-vibrational interference; RIXS; XAS; LVI; N2; O2; CO; H2O; OH;

    Sammanfattning : X-ray spectroscopy have been used to study the electronic structure of diatomic and cationic molecules. X-ray absorption spectra of the molecular cations N2+, O2+, and CO+ have been measured. LÄS MER

  7. 10. Multimode resonant X-ray scattering of free molecules

    Författare :Nina Ignatova; Victor Kimberg; Faris Gel’mukhanov; Sergey Polyutov; Hans Ågren; Piero Decleva; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; core-excited state; nuclear dynamic; wave-packet; resonant inelastic X-ray scattering; Franck-Condon; water; methanol; water isotopomer; pump-probe; quantum chemistry; ultrafast dissociation; Kemi; Chemistry; Fysik; Physics;

    Sammanfattning : This thesis is focused on the role that nuclear dynamics plays in the formation of X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectra of multimode free molecules. A combined approach based on ab initio electronic structure methods and quantum nuclear wave packet dynamics is applied to two systems -- water and methanol in the gas phase. LÄS MER