Free-Electron Laser interacting with Atoms and Molecules *

Free-Electron lasers have a very high photon energy, allowing inner electron ionisation of atoms and molecules. Leaving a hole in an inner orbital makes the system unstable leading to its decay until it reaches a more stable configuration. The system can alter its electronic configuration and energy by many processes such as Auger decay, shake-off or dissociation. At the same time, other photo-ionisations can occur, leading to a variety of possible paths the system can follow until it becomes stable

 

Using different pulses, we observe such mechanisms for molecular N2 and atomic Xe. For atomic Xe we investigate its interaction with laser pulses of energies 93, 115 and 850 eV. We compare our results of the ion yield with experimental results, and identify the pathways leading to the formation of each ion. For the 93 and 115 eV pulses we identify the main pathways leading to the formation of the 4+ and 5+ ions. For the 850 eV pulse we investigate the effect of pulse duration on the yields and pathways

For N2 molecules interacting with pulses of energy 525 and 1100 eV we investigate the parameters that favour the formation of the single-site and two-site double core hole states.