Divisions

Dr. Uwe Hergenhahn, Professor Alex Bradshaw

Research in this group focusses on the study of  atoms, molecules and clusters by electron spectroscopy using synchrotron radiation in conjunction with various techniques. Synchrotron radiation allows the electronic structure of matter to be probed by photoionization with light of high intensity and tuneable energy. Of particular interest are the dynamics initiated by the photoionization process and the relaxation of the ionized states. Current projects are:

• Autoionization of clusters, Interatomic and Intermolecular Coulombic Decay,
• High resolution electron-electron coincidence spectroscopy,
• Electron spectroscopy of free ions and mass selected ionic clusters.

Most experiments are carried out at the synchrotron radiation source BESSY in Berlin-Adlershof, where the group is currently situated. The measurements on a free ion beam are only possible by the extremely high integral flux of a Free Electron Laser. This project is carried out at the FLASH facility in Hamburg.

The results obtained are not only of fundamental interest in molecular physics and physical chemistry but also serve as a test bed for improving the technique of electron spectroscopy for applications in materials research, for example, in fusion research. Since partially ionized species are ubiquitous in the colder outer layers of fusion plasmas, this research is also of interest for the spectroscopic diagnosis of plasmas.