University of Connecticut

Events Calendar

Physics Colloquium

Friday, December 4, 2015
4:00pm – 5:00pm

Storrs Campus
Gant Science Complex, Physics, Room PB-38

Li Fang, Center for High Energy Density Science, University of Texas, Austin

“Photoionization of Midsize Systems with Free Electron Laser and XUV Laser Pulses”

The development of free electron lasers (FELs) has opened up the fields of investigating structural dynamics in photoionization and molecular dissociation at atomic spatial resolutions and nuclear motion time scales. We studied the intense FEL pulses induced ionization and fragmentation of midsize systems, C60 and Ho3N@C80 molecules. We developed a molecular model, which can be scaled well to larger systems, to reveal femotosecond molecular dynamics details. The comparison between the calculation and the experimental results of C60 molecules provides insights into the ionization processes of the molecules by FEL pulses. Our results illustrate that processes, such as photoelectric effect, secondary ionization, recombination and inter-atomic Auger decays, all play roles in the ionization that leads to the dramatic fragmentation of the resultant molecular ions.

XUV light from high harmonic generation (HHG) has been widely used to study single photon valence- and inner-valence-shell ionization as well as molecular dynamic with a-few-femtosecond or sub-femtosecond time resolutions. In the presented experiment, Ar clusters doped with SF6 were ionized using XUV photons of 32 eV picked from HHG generated with Ar gas. We will describe the experimental scheme and show the preliminary result of ion time-flight spectra taken at different cluster sizes, which hints to the influence of the cluster on the ionization of the dopant molecule.

Refreshments will be prior to the talk, at 3:30 p.m., in the Gant Complex, Physics Library, Room P-103.

Contact:

Dawn Rawlinson, 486-4916, dawn.rawlinson@uconn.edu

Physics Department (primary)

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