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.

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).