“Atomic Scale Imaging of Molecular Dynamics”

Martin Centurion, University of Nebraska-Lincoln Department of Physics

Understanding and controlling conversion of light into mechanical and chemical energy at the molecular level can have an impact across many fields, from biology to solar energy conversion and storage. These reactions often take place on the femtosecond time scale, and the motion of atoms is on the sub-Angstrom scale. While spectroscopic methods have been successful at following the dynamics of these reactions and establishing time scales, they lack the spatial resolution to map the structural dynamics. U sing ultrafast gas electron diffraction, we are now able to image photo-induced structural dynamics in isolated molecules with sub-200 fs resolution. We have captured the rotational motion of impulsively aligned Nitrogen molecules, and observed a coherent vibrational wavepacket in Iodine molecules. We are now moving from these initial proof-of-principle experiments and working on more complex reactions where we have captured bond-breaking and the ensuing structural rearrangements of the molecule.