X-Raying Laser-aligned Atoms and Molecules
Linda Young
Argonne National Laboratory
At the forefront of atomic, molecular and optical science have been recent developments of laser-based techniques to align and orient individual molecules in space. By allowing the study of "fixed-in-space" molecules and the control of the relative orientations of colliding molecules, the hope is that one day such techniques will significantly expand our understanding of fundamental physical and chemical processes. Furthermore, the ability to orient individual molecules is important for simplifying proposed single-shot imaging and structural determination of individual biomolecules. However, these laser alignment methods require relatively strong-fields (~1012 W/cm2 for small molecules) and the effect of these fields on the structure of the molecular framework is essentially unknown, either experimentally or theoretically. In this talk, I will summarize current experiments at the Argonne Advanced Photon Source that use strong-optical fields to create, and resonant polarized x-rays to probe, a macroscopic ensemble of orbitally-aligned krypton ions. By applying an external magnetic field, one can control the dynamics of the ion ensemble, i.e. suppress dealignment and induce coherent spin-precession. Analogous methods can be used to align molecules and detect the alignment. I will discuss the possibility of combining laser alignment techniques with x-ray probes from the proposed ERL to measure quantitatively the structure and dynamics of laser-aligned molecules.
