Speaker: Professor Marcos Dantus, Department of Chemistry, Physics and Astronomy (Michigan State University)
Program Description
When intense laser pulses interact with large polyatomic molecules (15-300 atoms) ionization and fragmentation takes place through a number of coherent and incoherent processes. Research in our group has focused on understanding and exploring how to control these processes through temporal shaping of the pulses. Our systematic search for coherence during the fragmentation process utilizes pulses designed to enhance/probe electronic or vibrational coherence. The simplest form of pulse shaping involves the creation of pulse replicas, such as those used for 2D electronic spectroscopy. These pulses can be scanned with attosecond resolution to interrogate the system immediately after tunnel ionization has occurred. Understanding intense laser-matter interactions is of both fundamental and applied importance. Results from our research deepen understanding of the behavior of matter under intense electromagnetic fields, the effect of multiple-electron excitation, correlated electronic motion, and the prospects of controlling matter using shaped femtosecond laser pulses. On the applied end of the spectrum, our group is well underway establishing femtosecond laser-induced ionization/dissociation (fs-LID) as a valuable ion activation method. Fs-LID leads to the observation of non-ergodic bond cleavage, making it an ideal approach for the mapping of post-translational modifications in proteins.
