Femtosecond electron sources for atomically-resolved dynamics and ultrafast high-resolution imaging

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Ultrafast lasers provided the “first light” in sufficiently short pulses to monitor atomic motion on the relevant timescales; below a millionth of a millionth of a second, to literally catch atoms on the fly as in stop-motion photography. However, the spatial resolution in conventional optical spectroscopy is limited to about the size of a big virus. This is about ten thousand times too coarse to observe the molecular structure at its finest detail, down to its fundamental building blocks – atoms. The progress in the development of ultrafast structure-sensitive cameras over the last 20 years has been tremendous, with large scale, kilometers long facilities such as LCLS (Stanford) built to provide us with the temporal and spatial resolutions required to observe atoms in motion. Germán Sciaini heads a group at the University of Waterloo that develops such “atomic-level” cameras in a compact design that fits on a table with the size of a standard office desk. His cameras are based on the use of ultra-short and bright electron bursts which can be applied to a wide range of structural problems. Our group develops home-built ultrafast electron diffraction setups which provide direct access to structural dynamics with atomic spatial and temporal resolutions. Special attention is paid to the study of strongly correlated transition metal oxides and organometallic materials. Dynamical studies of electron-electron, electron-phonon, and phonon-phonon interactions allow us to achieve an atomic-level understanding of structure-functional properties of novel materials. We also implement nanofluidics for the study of organometallic complexes in solution to investigate the effect of "d orbital" electronic degeneracy on the nuclear structure, i.e. Jahn Teller distortion. Another research area of great interest is the development of ultrafast cryo-electron microscopy. A new technique that will allow us to gain access to high-resolution (< 2 Å) structures of biomolecules at the single particle level without the need of crystallization. The long term goal of this research line involves structural studies of ribosomal-RNAs with atomic resolution. This research line is devoted to the investigation of the molecular basis of disease states at the atomic level of inspection. These studies are crucial for drug design aimed at the prevention of illness. These research programs are highly multidisciplinary and bridge ongoing efforts in the Department of Chemistry, the Quantum Matter Group in the Department of Physics, the Materials Engineering Group in Centre for Advanced Materials Joining, and the Institute of Biochemistry and Molecular Biology of Waterloo. Only 46 years ago, transition states, bond breaking and bond formation events were thought to be invisible and immeasurably fast. Nowadays, we have reached the spatial and temporal resolutions required to observe atoms in motion and, with that, been able to provide the most fundamental understanding of dynamical phenomena relevant to physics, chemistry, and biology. Our research is focused on this enabling technology, its fundamental science and its critical applications.