Time Resolved X-Ray Scattering of molecules in Solution: Approaching the Molecular Movie

The dissertation describes the use of Time-Resolved X-ray Diffuse Scattering (TR-XDS) to study photo-induced structural changes in molecules in solution. The application of the technique is exemplified with experiments on two bimetallic molecules. The main focus is on the data-flow and process of bringing the data from measurement to analysis.

Bridging the experimental design and challenges of the experiments from X-ray synchrotrons to the newly available X-ray Free Electron Laser sources (XFEL).LCLS in California is the first XFEL to come online and delivers intense 30fs X-ray pulses, orders of magnitude shorter than the 100ps X-ray pulses available from synchroton sources.

This increase in time-resolution allows for the use of X-ray techniques in a completely new time-domain, where coherent photo-induced changes in structure can be studied on their intrinsic time-scale. Measurements on Rh2(dimen)42+ obtained at European Synchrotron Radiation Facility (ESRF) are presented to exemplify TR-XDS at synchrotrons.

Similarly, measurements on Ir2(dimen)42+ are used to show the XFEL data-flow and how it deviates from the prior. A method to identify and account for systematic fluctuations in the purpose built CSPAD detector is presented and applied to the data to highlight the relevance of this work. Thereby showing the ability to capture a molecular movie on the sub-ps time-scale.