Mainz 2017 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 20: Poster Session I

A 20.24: Poster

Dienstag, 7. März 2017, 17:00–19:00, P OG1

Observing Ultrafast Dissociation of CH3Cl with a COLTRIMS-Reaction Microscope — •Gregor Kastirke, Miriam Weller, Kilian Fehre, Markus S. Schoeffler, and Reinhard Dörner — Institut für Kernphysik, Universität Frankfurt, Max-von-Laue-Str.1, 60438 Frankfurt, Germany

Ultrafast Dissociation can be observed after resonant photoexcitation of an innershell electron of a small molecular system like CH3Cl. Because of populating a strongly repulsive potential energy curve, the dissociation of the molecule takes place within a few femtoseconds. At some point during the dissociation, the molecule deexcites as an Auger Decay occurs. The emitted Auger Electron carries information on the internuclear distance of the molecular fragments at the instant of the decay. By measuring the momenta of the electron and ionic fragment in coincidence, different scenarios can be observed: An emission of the electron from a molecular orbital at early decay times, emission during the bond breakage and emission from an atomic orbital in cases the molecule completely dissociated into separated fragments. In order to investigate ultrafast dissociation in CH3Cl we performed the above mentioned experiment at the SOLEIL Synchrotron, France using a COLTRIMS setup. From the coincidence measurement of the Auger electron and the fragment ion, it is possible to yield molecular frame angular emission distributions of the electron. By furthermore exploiting the measured Auger electron energy, snapshots of the temporal evolution of a decaying orbital of a molecule fragmenting into separated atoms are obtained.