Ultrafast soft x-ray laser probing of core level molecular dynamics

• Applicant: Professorin Dr. Astrid M. Müller
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2001 to 2003
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5355312

The proposed work focuses on the investigation of time-resolved dissociation and molecular reaction dynamics monitoring core level photoelectron spectroscopy. The experiments will be performed using a fully operational apparatus which consists of a Ti:sapphire laser system, a pulsed jet of rare gas species for harmonic generation, harmonic separation by two grazing incidence gratings, a vacuum chamber for sample introduction, and a magnetic bottle time-of-flight electron spectrometer for kinetic energy analyses of the resulting photoelectrons. Pump-probe measurements will take advantage of the femtosecond time resolution capability of this new x-ray source by detecting the changes in electron orbital configurations as a function of internuclear separation in dissociative states in real time. The x-ray laser source will be used to explore core level shifts in the Al2Br6 molecule, which has both bridging and terminal Br atoms and can dissociate to form two AlBr3 molecules or eject Br2 and Br products, prior to and during its fragmentation. Because the core level shifts provide direct information about the chemical environment and bonding of atoms in molecules it should be possible to distinguish between the two types of Br atoms in Al2Br6. Optimal control techniques will then be used to create a wave packet on the dissociative potential energy surface of the Al2Br6 molecule which leads to the formation of specific products. The different products, which will depend on the particular shape of the pump pulse, will be detected in real time using core-level photoelectron spectroscopy.

• DFG Programme: Research Fellowships