Univ.-Prof. Dr. Martin K. Beyer
Chemical Physics
The Chemical Physics group at the Department of Ion Physics and Applied Physics investigates mechanisms of chemical reactions under idealized conditions. For the experiments, we use high-resolution mass spectrometers to investigate isolated clusters under ultra-high vacuum conditions. Lasers from the Innsbruck Laser Core Facility are used for spectroscopy and photochemistry. An atomic force microscope is used to mechanically force chemical reactions in individual polymer molecules. Quantum mechanical calculations explain the experimental observations. We use these methods to investigate the nature of chemical bonds and explain a wide range of phenomena, from the photochemical ageing of sea salt aerosols in the atmosphere, molecular catalysts and iron-containing molecules in space to polymer functional materials.
In the ion trap in the ultra-high vacuum of a mass spectrometer, chemical reactions take place in slow motion because only about one collision of a cluster with a molecule of a reaction gas takes place per second. This allows us to follow the course of the reaction precisely. Furthermore, we use tunable lasers to initiate photochemical reactions and to determine the structure of the clusters and their reaction products. With these methods, we investigate the behavior of sea salt aerosols in the atmosphere as well as hydrogen evolution reactions at metal ions solvated in a water cluster, gaining insight into the fundamental properties of chemical bonds.
Sodium chloride clusters doped with glyoxylate serve as a model system for sea salt aerosols in the Earth's atmosphere.
Despite decades of research, the chemistry of iron in interstellar clouds holds more questions than answers. In the mass spectrometer, we can simulate the vacuum conditions found in space. We vaporize iron with a short laser pulse and mix the iron vapour with gas in the ion source to produce charged, reactive iron compounds similar to those in space. We inject these into the mass spectrometer and examine them further with lasers and other reaction partners. This provides us with data that can be compared with astronomical observations to ideally identify iron complexes in interstellar clouds.
With the infrared spectrum of Ar2FeH+ we presented the first spectrum of the FeH+ molecular ion expected in the interstellar medium.
Polymeric functional materials based on mechanophores promise novel material properties, e.g. the self-healing of bond ruptures or the indication of mechanical overload by a color change. We are investigating the mechanical forces that trigger these functions with individual molecules. Using the atomic force microscope, a single molecule is anchored between a surface and a microscopically small tip and mechanically clamped. We measure the force with which a chemical reaction, e.g. the breaking of a chemical bond or the activation of a latent catalyst, is enforced.
A latent catalyst is mechanically activated: The mechanical load exposes a binding site at the copper ion. This is a prerequisite for a catalytic reaction.