Speakers
Description
Cryogenic ion-trap vibrational spectroscopy is a valuable method to study molecular structure and the strength of inter- and intramolecular interactions. The Asmis group uses infrared photodissociation (IRPD) spectroscopy on mass-selected clusters in the gas phase, making use of the Free Electron Laser at the FHI, to study their structure, reactivity and dynamics, with the goal to bridge the knowledge gap between isolated, small particles in the gas phase and condensed matter. Two main projects are developed at the FHI-Asmis group, i. metal oxide clusters in the gas phase and ii. chiral selector IRPD spectroscopy.
The understanding of heterogeneous catalysis cannot be achieved without experimental model catalysts that reduce the complexity of supported metal or metal oxide catalysts. Therefore, metal oxide clusters in the gas phase are aimed at gaining a better atomistic understanding of single-site catalysts. Our group has many years of expertise on combining state-of-the-art mass spectrometric and infrared spectroscopic experiments with quantum chemical calculations to ultimately gain molecular-level insights into the geometric structure of, and C-H and O-H bond activation by mixed metal oxide clusters.
The second area aims to study chiral selector IRPD spectroscopy. The handedness of drugs, agrochemicals and flavors is crucial for their properties and characterization methods that can recognize, distinguish and quantify enantiomers are required. We transfer chiral analytes present in an enantiomeric mixture into the gas phase, where they form complexes with a volatile chiral selector. The respective diastereomers can be spectrally differentiated and the enantiomeric excess in solution is determined by this gas phase approach, with minimal sample and time consumption, and with satisfactory accuracy.
Future studies of these and related systems will make use of an instrument upgrade that will add a mass selection and reaction stage to our current setup. This will allow to perform reactions at different temperatures, at different partial pressures and with different gases. Also, reaction product ions are mass- selected before they are trapped, adding another stage of selectivity to the experiment.
