Controlled Molecule Imaging
The independent CFEL research group Controlled Molecule Imaging develops innovative methods to obtain full control over large molecules and to apply these methods and the created controlled samples in fundamental physics and chemistry studies. The group is headed by Jochen Küpper and embedded in the Coherent Imaging Division of DESY and Universität Hamburg at the Center for Free-Electron Laser Science (CFEL).
The European Research Council (ERC) supports our work through the Consolidator Grant research project "Controlling the Motion of Complex Molecules and Particles" (COMOTION), which provides two million euros for 5 years to further the research on control of complex molecules.
Understanding and controlling chemical reaction dynamics defines a challenging scientific area where in the last decades different instruments have been developed to determine which specific motions, amid the myriad of possibilities, lead a system to the product of the reaction. This marks the miracle of chemical systems: there are usually only a few modes that direct the process by virtue of the exponential dependence on energetics hidden within a complex potential energy landscape. For all but a few simple molecules, we have poorly resolved “maps” of these potential energy surfaces to guide us; yet chemists harness the power of stored chemical potential routinely without full knowledge of the process.
We will advance new means of following chemical reaction dynamics to refine our maps of the forces at play with the goal of implementing electromagnetic-field-based control methodologies. We develop methods to create clean samples of individual species, based on the spatial separation of molecular quantum states, structural isomers, and cluster sizes. These clean samples are further controlled to fix the molecules in space, i.e., they are laser aligned and mixed-field oriented. These controlled ensembles are ideal samples for the investigation of molecular structure and dynamics in novel imaging experiment, such as electron and x-ray diffraction, ion and photoelectron imaging, a.s.f.