Study and control of reactive collisions in the quantum regime*

In the area of cold and controlled collisions, we try to unravel the fundamental nature of chemical reactions by controlling the quantum states of the reaction partners and by carrying out the experiments at temperatures near absolute zero, e.g., in order to find out about the properties of short-lived reaction intermediates. In this temperature regime, the wave properties of matter dominate chemical reactivity. For instance, reaction products can be formed via quantum tunneling, even though the energy of the reaction partners is classically not sufficient to overcome the potential barrier. Besides a fundamental understanding of chemical reactivity, this research also allows for a better knowledge of chemical reactions in the interstellar medium, where low-temperature and low-pressure molecular clouds are exposed to high-energy cosmic radiation.

One focus of my group is on so-called chemi-ionization processes in the gas phase, in which an atom or molecule is ionized by another species in a long-lived, electronically excited (metastable) state. In this talk, I will present different means to control chemi-ionizing collisions by quantum-state preparation.