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Diffractive Imaging Of Laser Induced Molecular Reactions With Kiloelectron-Volt Ultrafast Electron Diffraction, Yanwei Xiong
Diffractive Imaging Of Laser Induced Molecular Reactions With Kiloelectron-Volt Ultrafast Electron Diffraction, Yanwei Xiong
Department of Physics and Astronomy: Dissertations, Theses, and Student Research
Capturing the structural changes during a molecular reaction with ultrafast electron diffraction (UED) requires a high spatiotemporal resolution and sufficiently high signal-to-noise to record the signals with high fidelity. In this dissertation, I have focused on the development of a tabletop gas phase keV-UED setup with a femtosecond temporal resolution. A DC electron gun was employed to generate electron pulses with a high repetition rate of 5 kHz. The space charge effect in the electron pulse was ameliorated by compressing the 90 keV electron pulse longitudinally with a time varying electric field in an RF cavity. The velocity mismatch between …
Gas-Phase Electron Diffraction From Laser-Aligned Molecules, Jie Yang, Martin Centurion
Gas-Phase Electron Diffraction From Laser-Aligned Molecules, Jie Yang, Martin Centurion
Martin Centurion Publications
Electron diffraction is a valuable tool to capture structural information from molecules in the gas phase. However, the information contained in the diffraction patterns is limited due to the random orientation of the molecules. Additional structural information can be retrieved if the molecules are aligned. Molecules can be impulsively aligned with femtosecond laser pulses, producing a transient alignment. The alignment persists only for a time on the order of a picosecond, so a pulsed electron gun is needed to record the diffraction patterns. In this manuscript, we describe the alignment process and show the changes in the diffraction pattern as …