A new route for enantio-sensitive structure determination by photoelectron scattering on molecules in the gas phase.

X-Ray as well as electron diffraction are powerful tools for structure determination of molecules. Studies on randomly oriented molecules in the gas phase address cases in which molecular crystals cannot be generated or the interaction-free molecular structure is to be addressed. Such studies usually yield partial geometrical information, such as interatomic distances.

Double Core-Hole Generation in O_{2} Molecules Using an X-Ray Free-Electron Laser: Molecular-Frame Photoelectron Angular Distributions.

We report on a multiparticle coincidence experiment performed at the European X-ray Free-Electron Laser at the Small Quantum Systems instrument using a COLTRIMS reaction microscope. By measuring two ions and two electrons in coincidence, we investigate double core-hole generation in O_{2} molecules in the gas phase. Single-site and two-site double core holes have been identified and their molecular-frame electron angular distributions have been obtained for a breakup of the oxygen molecule into two doubly charged ions.

Zeptosecond birth time delay in molecular photoionization.

Photoionization is one of the fundamental light-matter interaction processes in which the absorption of a photon launches the escape of an electron. The time scale of this process poses many open questions. Experiments have found time delays in the attosecond (10 seconds) domain between electron ejection from different orbitals, from different electronic bands, or in different directions.

Link between Photoelectron Circular Dichroism and Fragmentation Channel in Strong Field Ionization.

The investigation of the photoelectron circular dichroism (PECD) in the strong field regime (800 nm, 6.9 × 10 W/cm) on methyloxirane (MOX) reveals a flip of the sign of PECD between different fragmentation channels. This finding is of great importance for future experiments and applications in chemistry or pharmacy using PECD in the strong field regime as analysis method.

Observation of Enhanced Chiral Asymmetries in the Inner-Shell Photoionization of Uniaxially Oriented Methyloxirane Enantiomers.

Most large molecules are chiral in their structure: they exist as two enantiomers, which are mirror images of each other. Whereas the rovibronic sublevels of two enantiomers are almost identical (neglecting a minuscular effect of the weak interaction), it turns out that the photoelectric effect is sensitive to the absolute configuration of the ionized enantiomer. Indeed, photoionization of randomly oriented enantiomers by left or right circularly polarized light results in a slightly different electron flux parallel or antiparallel with respect to the photon propagation direction-an effect termed photoelectron circular dichroism (PECD).

Imaging the He2 quantum halo state using a free electron laser.

Quantum tunneling is a ubiquitous phenomenon in nature and crucial for many technological applications. It allows quantum particles to reach regions in space which are energetically not accessible according to classical mechanics. In this "tunneling region," the particle density is known to decay exponentially.