Speaker: Xiaojun Wang, Department of Physics and Astronomy, University of Nebraska-Lincoln
Program Description:
Electron transfer is an important process in chemistry and biology, where an electron from an ion transfers to a neutral molecule and triggers a dissociation reaction. The electron transfer process has been widely investigated using photoelectron 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 seminar, we will talk about the design and implementation of an apparatus to investigate the electron transfer process and the resulting fragments after photoexcitation of ion-molecule clusters[1]. 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 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.
Reference: [1] Wang, X., Hasan, M., Fan, L., Wang, Y., Li, H., Slaughter, D.S. and Centurion, M., 2023. Mass-selected Ion-molecule Cluster Beam Apparatus for Ultrafast Photofragmentation Studies. arXiv preprint arXiv:2303.00225.
