Nicolas Douguet, Kennesaw State University
When
Where
Abstract: The new generation of attosecond light pulses, from vacuum ultraviolet to soft x-rays, and the availability of high-intensity lasers in the near-infrared region, have opened up a field of new possibilities to study and control the real-time electron dynamics in atoms and molecules. Thirty years after the femtochemistry revolution, we are witnessing the birth of attochemistry, a field where new compounds could be designed, and unconventional reactions become possible via the control the electron-density in molecules. In this talk, I will consider a variety of processes where attosecond and femtosecond pulses enable to unravel electronic motion in molecules at its natural time scale. First, I will discuss circular and magnetic dichroism in oriented Li and He+ atoms to investigate dichroic properties of matter. It will also be shown that intense optical fields can be used to track the tunneling mechanism of an electron and allow us to understand atomic excitation in strong fields, while Bohmian mechanics constitutes an interesting theoretical tool to interpret these processes. Next, I will present various new interferometric techniques with attosecond pulse trains which enable resolving rapid phase variation of an attosecond wavepacket before turning to the fascinating applications of attosecond physics to molecules. After introducing our new time-dependent numerical methods to describe multi-electron systems in ultra-short pulses, I will show that interferometric schemes with counter-rotating light have the potential to discriminate enantiomers in randomly oriented chiral molecules. Using an attosecond pulse, I will also demonstrate that the dynamics of a highly energetic photoelectron, temporarily confined in a diatomic molecule, can be revealed. In addition, the coherence of the produced vibrationally excited cation can survive, and the harmonic motion of the molecule in phase space experiences a time delay that can be controlled by varying the central pulse frequency. Finally, I will discuss roads toward attochemistry and propose methods to track and even control charge migration in a molecule. I will conclude by presenting our future theoretical developments to describe time-resolved x-ray and light-assisted electron scattering; two very promising techniques to provide snapshots of a chemical reaction. ** Refreshments served from 2:45pm – 3:00pm in PAS 218. Thank you. **