Electron–electron interactions in atoms

The dynamic of electrons in the vicinity of a nucleus is fundamental for most atomic interactions and in general characterized by its enormous speed. Apart from the Coulomb binding potential, the dynamics of individual electrons in an atom is also dominated by the pair wise interaction between the electrons.

This project focuses on methods that allow investigating the temporal evolution of charge-transfer inside atoms. Based on them, it is possible to develop a better understanding of the involved processes and to improve theoretical models describing them. The studies performed in the framework of this MAP project are focused on developing and employing short-pulse lasers emitting pulses comprising of merely 1.5 field cycles of visible light.

Our experiments benefit in two ways from this technology: First, the interaction of charged particles with electric fields is well understood, facilitating the analysis and interpretation of the acquired data. Secondly, the short-pulse laser sources developed within this project are sources for the routine generation of the shortest controllable signals and thus ideal tools for the investigation of ultrafast processes. Based on the frequency conversion of this high-power laser pulses by high-order harmonic generation, the spectral extent of the light is shifted into the extreme ultraviolet (XUV) yielding the shortest pulses demonstrated enabling studies with a temporal resolution reaching the atomic unit of time (24 attoseconds).