Argonne National Laboratory

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New Techniques for Probing and Controlling Nonadiabatic Molecular Dynamics

XSD/AMO Special Presentation
Vladimir S. Petrovic, Stanford University
July 11, 2014 2:00PM to 3:00PM
Building 401, Room A1100
On the molecular level the conversion of energy from one form to another occurs via nonadiabatic interactions that govern the exchange of energy between different degrees of freedom. Often this exchange occurs on fast timescales, which makes time-resolved pump-probe techniques suitable for studying it. In the first part of the talk I will report on using time-resolved dissociative ionization to probe structural changes that result from nonadiabatic interactions.

This technique relies on the characterization of the dissociation-formed fragments, their correlations, or their coincidences. I will discuss complementary methods of initiating dissociative ionization via weak-field x-ray absorption or strong-field IR absorption for investigation of nonadiabatic processes that lead to unimolecular isomerizations in small hydrocarbons. In particular, dynamics at conical intersections can be studied and controlled using short-pulse x-ray and intense IR radiation.

In addition, I will discuss more recent experiments performed at Linac Coherent Light Source that investigate ultrafast x-ray initiated molecular dynamics. In the second part of the talk I will talk about plans to extend the application of these techniques to more complex multi-electron and aqueous systems. These experiments seek to generate insight relevant for optimizing conditions for diffraction-before-destruction techniques in biologically relevant systems.