An ability to identify, tag, and follow unambiguously quantum trajectories during the movement of charges in molecular systems is central to addressing question that are key to unlocking solutions to an array of contemporary scientific and technical challenges - understanding the chemistry of interstellar media, reducing our carbon footprint, enabling efficient, clean energy sources, and controlling dynamics in biological molecules are just a few examples. Photoinduced charge dynamics, for example, is ubiquitous in catalyses, photosynthesis, photovoltaic effect, radiation damage in biomolecules and atmospheric chemistry. With clock speeds of order 1fs, the energy flow and correlated dance between electrons and atomic nuclei require attosecond temporal resolution and carefully-designed experimental techniques to track reliability. The focus of a joint effort between the University of Maryland and the University of Central Florida is on photoinduced charge dynamics in important prototype molecules. Specifically, charge dynamics is being probed via transient absorption of core-level states of carbon.

We are also developing a phase-sensitive tool to explore electron dynamics with femtosecond pulses. The photo ionization of a system by a pair of phase-locked pulses leading matter wavepacket interference in the continuum--quantum interference (QuI). QuI is believed to provide information about charge-density motion as well as the phase of that motion relative to the driving field. Pulse pairs are created with a Mach-Zehdner interferometer with one variable arm making the tool usable over a wide range of timescales (femtosecond to attosecond) and frequencies (from the near IR to the XUV).

Ultrafast Research Pages

Femtosecond Experiments

Attosecond Experiments

Group Lead

Wendell T. Hill

(301) 405 4813

wth@umd.edu

Room B0165 Physical Sciences Complex

Building 415, University of Maryland

College Park, MD 20742

301-314-2012

This work is supported by the National Science Foundation