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Author: Elsaesser, T. × End date: 2024 × Start date: 2020 × Start date: 2000 × DDC: 530 × Has files: Yes × Type: Text × Publisher: Les Ulis : EDP Sciences ×

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Now showing 1 - 6 of 6
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    Ultrafast structural and vibrational dynamics of the hydration shell around DNA
    (Les Ulis : EDP Sciences, 2013) Elsaesser, T.; Szyc, LŁ.; Yang, M.
    Two-dimensional infrared spectroscopy in the frequency range of OH- and NH stretch excitations serves for a direct mapping of hydration dynamics around DNA. A moderate slowing down of structural dynamics and resonant OH stretch energy transfer is observed in the DNA water shell compared to bulk water.
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    Ultrafast inter-ionic charge transfer of transition-metal complexes mapped by femtosecond x-ray powder diffraction
    (Les Ulis : EDP Sciences, 2013) Zamponi, F.; Freyer, B.; Juvé, V.; Stingl, J.; Woerner, M.; Chergui, M.; Elsaesser, T.
    Transient electron density maps are derived from x-ray diffraction patterns of photoexcited [Fe(bpy)3]2+(PF6 -)2 powder. Upon photoexcitation, the 5T 2 quintet state reveals a charge transfer from the PF 6- ions and from the Fe atoms to neighboring bpy units. The charge transfer from the Fe points to a partial and weak charge-transfer character of this state.
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    Femtosecond x-ray diffraction using the rotating crystal method
    (Les Ulis : EDP Sciences, 2013) Freyer, B.; Stingl, J.; Zamponi, F.; Woerner, M.; Elsaesser, T.
    We demonstrate the rotating-crystal method in femtosecond x-ray diffraction. Structural dynamics of a photoexcited bismuth crystal is mapped in a pump-probe scheme by measuring intensity changes of many Bragg reflections simultaneously.
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    Ultrafast two-dimensional THz spectroscopy of graphene
    (Les Ulis : EDP Sciences, 2013) Bowlan, P.; Martinez Moreno, E.; Reimann, K.; Woerner, M.; Elsaesser, T.
    With two-dimensional THz spectroscopy the dynamics of low-energy carriers in graphene is determined. Both intra- and interband absorption contribute to the observed ultrafast pump-probe signals.
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    Ultrafast charge relocation in an ionic crystal probed by femtosecond x-ray powder diffraction
    (Les Ulis : EDP Sciences, 2013) Woerner, M.; Zamponi, F.; Rothhardt, P.; Stingl, J.; Elsaesser, T.
    Transient electron density maps of potassium dihydrogen phosphate(KH 2PO4, KDP) are derived from femtosecond x-ray powder diffraction patterns. Upon photoexcitation, the low-frequency TO soft mode is elongated impulsively and modulates the electronic charge distribution on the length scale of interatomic distances, much larger than the vibrational amplitude of the nuclear motion. The results demonstrate a charge transfer from the volumes around the P-atoms to those containing the O - H·· ·O units and a quadrupolar distortion of the K+ charge distribution. This behavior reflects the interplay of nuclear motions and electric polarizations in the ionic crystal lattice.
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    Ultrafast IR pump-probe and 2D-IR photon echo spectroscopy of adenosine-thymidine base pairs
    (Les Ulis : EDP Sciences, 2013) Greve, C.; Preketes, N.K.; Costard, R.; Koeppe, B.; Fidder, H.; Nibbering, E.T.J.; Temps, F.; Mukamel, S.; Elsaesser, T.
    We characterize diagonal and off-diagonal anharmonicities of N-H stretching vibrations in adenosine and thymidine monomers and in A•T-base pairs in chloroform solution, showing the important role of coupling between vibrationally excited N-H stretching states.