Physics Colloquium, January 15, 2008
Crystallography in Five Dimensions: Capturing the Act of Atoms on Nanointerfaces Chong-Yu Ruan

Michigan State University

Ultrafast molecular imaging represents a new emerging frontier. In particular, recent developments in the ultrafast electron diffraction have demonstrated the ability to image the rearrangements of chemical bonds in complex structures with resolutions of picometer and femtosecond. These new limits provide the means for characterizing transition state, including excited state and nonequilibrium structures of complex energy landscapes. By freezing atomic configuration on the ultrafast timescale, we are able to develop concepts that correlate structure with function. Examples include structure-driven radiationless process, dynamics-driven phase transition, and nonequilibrium structures exhibiting negative temperature, bifurcation, or selective energy localization in bonds. New development in electron nanocrystallography, with its unique sensitivity to nanostructured materials and detecting single charge transfer event at interfaces, opens a window of opportunity to investigate phenomena on the nanometer scale, with specificity to different components, and proving correlation map in energy and space-time coordinates. In this talk, I will present the effort made so far in this direction based on the studies on nano-carbons and nanoparticle-molecule-substrate interfaces using time-resolved nanodiffraction technique.

Dr. Ruan's Web Site

4:00 p.m., Physics Research Building (PRB), Room 1080

Reception at 3:45 p.m., Atrium, PRB