Erlangen 2018 – scientific programme

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A: Fachverband Atomphysik

A 37: Clusters IV (joint session MO/A)

A 37.5: Talk

Thursday, March 8, 2018, 11:45–12:00, PA 2.150

Velocity Map Imaging of the Photo-induced Dissociation of Mass-selected Cation Complexes — •Daniel Leicht, Brandon M. Rittgers, and Michael A. Duncan — University of Georgia, Athens, USA

We employ a velocity map imaging mass spectrometer to study the photo-induced dissociation of mass-selected ionic molecular complexes. Ions are produced in a molecular beam and pulse extracted in a linear time-of-flight mass spectrometer. After mass selection, the ions are intersected with a laser beam, leading to dissociation. The fragments are then detected with spatial resolution by multichannel plates and a phosphor screen. From the spatial distribution of fragments we can extract the kinetic energy release of the dissociation process.

Excitation of Ag⁺-benzene and Ag⁺-toluene with 355 nm leads to the exclusive formation of benzene⁺ and toluene⁺ fragments, respectively. This is indicative of a dissociative charge transfer process. On the other hand, irradiation of Zn⁺-acetylene with 266 nm leads to the formation of both, Zn⁺ and acetylene⁺ fragments. Apparently, two different photo-initiated dissociation pathways take place in this system.

The observed kinetic energy release in all of these systems can provide information about the binding energy and, given sufficient resolution, the population of quantum states in the fragment ions.