Date of Award
Doctor of Philosophy (PhD)
Margaret M. Murnane
Henry C. Kapteyn
To fully understand atomic and molecular dynamics scientists must be able to probe and study dynamics on their fundamental time scales. The motion, structure, and arrangement of molecules play a fundamental role in chemical reactions. Analyzing these reactions is not only important for their immediate insights but the understanding is essential for the progress of many areas of science and technology including biology, material science, and medicine.
These dynamics require a light source with not only the time resolution to capture attosecond and femtosecond dynamics but one that can also reach a large energy range of interesting processes. High harmonic generation (HHG) provides a tunable coherent light source of high energy photons while remaining table-top in size. These highly excited states can be fully analyzed using coincidence electron and ion spectroscopy performed short time-scale resolution.
The combination of high harmonic generation with coincidence spectroscopy allows for the study of a variety of atomic and molecular systems. We were able to observe a new ionization pathway enabled by intense laser fields in argon and xenon. With helium, we demonstrate the ability to optically induce full electromagnetic transparency. The time resolved dissociation of bromine allowed for the understanding of how molecular orbital structure changes to become atomic in nature. In hydrogen we considered the interaction of electronic and nuclear wavepackets in a non-Born-Oppenheimer regime in a new level of detail. We explore the coherent control in dissociating a triatomic molecule with N2O showing the ability to optically control the dissociation pathway of the molecule. Additional molecules including the argon dimer, ethylene and ozone have also been studied and analysis points to very interesting dynamics.
Hogle, William Craig, "High Harmonic Driven Attosecond and Femtosecond Molecular Dynamics" (2014). Physics Graduate Theses & Dissertations. 118.