Atomic, Molecular and Electron Physics
Laser-based experimental methods and laser-induced processes
Research fields (AG Hotop)
Our research was focussed on studies of elementary collision processes in atomic, molecular and electron physics:
- Photoexcitation and –ionization of atoms with lasers;
- Penning ionization of atoms and molecules in thermal collisions with excited atoms;
- Formation of negative ions in collisions of state-selected Rydberg atoms or slow free electrons (energy width ≤ 1 meV) with molecules and molecular clusters;
- Angle-differential scattering of low-energy electrons from free atoms and molecules at very high resolution (energy width down to 4 meV).
These processes were investigated in detail with atomic and molecular beam experiments including laser-based electron sources and state-selection techniques. The main goal is the basic physical understanding of the studied processes which are important in many environments (low temperature plasmas including discharges, gaseous dielectrics and laser media, atmospheric physics, trace detection). The experiments resulted in quantitative data for the energy-dependent probabilities (cross sections) for the processes of interest. These data were compared with the results of ab initio calculations, carried out in cooperation with theorists (Prof. Wilfried Meyer, TU Kaiserslautern; Prof. Ilya I. Fabrikant, Lincoln, Nebraska, USA; Prof. Victor L. Sukhorokov and Prof. Ivan D. Petrov, Rostov-on-Don, Russia).
A special topic of our experimental work was the development and the use of special laser-based methods in atomic, molecular, and electron physics.
Our projects have been supported by the Deutsche Forschungsgemeinschaft, by the research center OTLAP (Optische Technologien und Lasergesteuerte Prozesse) at TU Kaiserslautern and by the European Science Foundation (network EIPAM, i.e. Electron-Induced Processing At the Molecular level).