CFEL-DESY Theory Division
The CFEL-DESY Theory Division develops theoretical and computational tools to predict the behavior of matter exposed to intense electromagnetic radiation. We employ quantum-mechanical and classical techniques to study ultrafast processes that take place on time scales ranging from picoseconds (10-12 s) to attoseconds (10-18 s). Our research interests include the dynamics of excited many-electron systems; the motion of atoms during chemical reactions; and x-ray radiation damage in matter.
Research Highlights
Time-resolved observation of band gap shrinking and electron-lattice thermalization in x-ray excited GaAs
11 December 2015
The paper titled "Time-resolved observation of band-gap shrinking and electron-lattice thermalization within X-ray excited gallium arsenide" by Beata Ziaja, Nikita Medvedev, Victor Tkachenko, Theophilos Maltezopoulos, and Wilfried Wurth, published on-line on Dec. 11, 2015 in Nature's Scientific Reports, proposes a new method for measuring the rate of energy exchange between excited electrons and atomic lattice in laser-excited semiconductors.
Ultrafast charge transfer of a valence double hole in glycine driven exclusively by nuclear motion
02 October 2015
Atomic motion can drive charge transfer on unexpectedly short time scales. When the electron cloud of a molecule is hit by an ultrashort burst of light, complex processes ensue. One or more of the very light and fast electrons can suddenly be kicked out, forcing the other electrons to quickly relocate on time scales as short as just a few femtoseconds (1 fs = 0.000000000000001 s). Only at much longer times do the heavier atomic nuclei respond and play a role in the redistribution of electrical charge.
Sensitivity of nonlinear photoionization to resonance substructure in collective excitation
09 April 2015
The year 2014 marked the 50th anniversary of the discovery of the 4d giant dipole resonance in atomic xenon (nuclear charge Z=54). The three outermost electron shells of xenon (from outside to inside) are 5p, 5s, and 4d.
