Dr. T. Elsaesser, Max-Born-Institute, Berlin: How atoms and charges move in crystals - x-ray diffraction in the femtosecond time domain
|15 November 2012||FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Dr. Thomas Elsaesser|
|Title:||How atoms and charges move in crystals - x-ray diffraction in the femtosecond time domain|
|Start:||16.00 (Doors open and coffee available at 15.30)|
|Host:||Thomas la Cour Jansen|
Numerous functional processes in condensed matter involve atomic motions and charge relocations on ultrashort time scales. X-ray diffraction methods with a femtosecond time resolution allow for spatially resolving transient structures and charge distributions in a most direct way, providing new insight into the structure-function relationship of crystalline materials. This talk combines an introduction into this research field with a discussion of recent results onstructural dynamics of ionic crystals. Experiments with laser-driven hard x-ray sources reveal the interplay of lattice and charge motions in the photoexcited prototype material KDP (KH2PO4).Upon elongation of the soft mode, a low-frequency lattice vibration, electrons are relocated over the length of a PO bond which is 100 times larger than the vibrational amplitude. As a second example, the field-driven transfer of valence electrons between ions in a superposition of quantum states of LiBH4 will be addressed.
|Last modified:||12 September 2014 11.21 a.m.|