Berlin 2014 – wissenschaftliches Programm
MO 5.11: Poster
Montag, 17. März 2014, 16:30–18:30, Spree-Palais
H+ + Cl−: Photoion pair production in HCl studied by bipolar three-dimensional (3D) photoion pair imaging — •Christof Maul1, Mikhail Poretskiy1, Alexey Chichinin2, and Karl-Heinz Gericke1 — 1Institut für Physikalische und Theoretische Chemie, TU Braunschweig — 2Institute of Chemical Kinetics and Combustion, Novosibirsk, Russia
Ion pair production is one of several competing processes occurring in many molecules. It has been studied intensively by photoexcitation in the vacuum ultraviolet (VUV) wavelength range. Complementing these studies, we report a resonance enhanced multi-photon ionization (REMPI) technique using readily available UV light and 3D imaging in order to simultaneously monitor the oppositely charged ionic products.
The advantage of this approach is that we can exclusively address the photoion pair among numerous competing processes. Moreover, much larger portions of the relevant potential energy surfaces can be interrogated than in single photon VUV experiments. 3D distributions of fragment momentum vectors can be determined containing the complete information about the fragmentation process with kinetic energy and spatial fragment distributions or anisotropy parameters as subsets.
We demonstrate the method for HCl fragmentation as prototype because HCl is known for photoion pair production, and its fragmentation dynamics have intensively been studied. From our data, the existence of a Rydberg gateway state for photoion pair generation is verified. The approach can easily be applied to any molecule exhibiting a potential energy surface with attractive part at large internuclear distances.