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Mass-Selected Ion-Molecule Cluster Beam Apparatus for Ultrafast Photofragmentation Studies (MICBAUPS)

Xiaojun Wang, University of Nebraska - Lincoln


Electron transfer is an important process in chemistry and biology, where an electron from an anion transfers to a neutral molecule and triggers a dissociation reaction. The electron transfer process has been widely investigated using photoelectron imaging such as velocity mapping imaging in the past twenty years. The detection of fragments including fragment-ions and neutrals is equally important to understand the electron transfer process, especially the dissociation. In this thesis, we will talk about the design and implementation of a novel apparatus to investigate the excited-state dissociation dynamics of mass-selected ion-molecule clusters by mass-resolving and detecting photofragments: fragment ions and neutrals. Here, the dissociation of the ion-molecule cluster in the excited state is triggered by the electron transfer. The apparatus includes the generation of the ion-molecule clusters in a source chamber, separation and selection of the parent ion-molecule cluster using a TOF mass spectrometer and mass filter, and detection of photofragments after laser excitation of ion-molecule clusters using linear-plus-quadratic reflectron mass spectrometer. We have carried out experiments on the CF3I∙I- ion-molecule cluster photoexcited by 266~nm UV femtosecond laser pulses to demonstrate the instrument performance. Anion fragments I- and CF3I- are detected along with neutral fragments. We will compare the experimental results with our electronic structure calculation and the prior work, and discuss the dynamics of the photoexcited cluster.

Subject Area

Physics|Applied physics|Particle physics

Recommended Citation

Wang, Xiaojun, "Mass-Selected Ion-Molecule Cluster Beam Apparatus for Ultrafast Photofragmentation Studies (MICBAUPS)" (2023). ETD collection for University of Nebraska - Lincoln. AAI30574492.