Ultrafast High Harmonic, Soft X-Ray Probing of Molecular Dynamics
Abstract
A three year program of experimental measurements in molecular dynamics was completed, using ultrafast soft x-rays produced by the method of pulsed laser high order harmonic generation and the vacuum ultraviolet synchrotron beamline at the Advanced Light Source. The experiments explored both small molecules and the intact ionic liquid molecules in the gaseous phase. Investigations probed the formation of intact ion pairs of aprotic ionic liquids in the vapor phase, the ultrafast fragmentation dynamics of ionic liquids, and the thermal decomposition of hypergolic ionic liquids, the latter in collaboration with Steven Chambreau and Ghanshyam (Gammy) Vaghjiani of Edwards Air Force Research Laboratory. Ionic liquids and cluster species have unique structures that involve the coupling of electron dynamics with vibrational, i.e. nuclear, motions. Thus the photofragmentation and decomposition pathways of ionic liquids are poised to undergo proton and electron transfers (charge transfer in excited electronic states) and reactive chemistry that are unlike most molecules when promoted to low energies of excitation. To understand this unique chemistry, these pathways were investigated by powerful methods to determine the novel internal reactive chemistry that will occur. Experiments were also performed on superexcited states of nitrogen. X-ray sources based on ultrafast lasers offer promise to complement synchrotron radiation as a convenient and more widely available means for chemical analysis, which will be of great interest to the Air Force and for the training of students. The goal of this research is to study ultrafast processes in molecular systems relevant to chemical and material properties of interest to the Air Force.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 16, 2009
- Accession Number
- ADA513755
Entities
People
- Stephen R. Leone
Organizations
- University of California, Berkeley