Studies On Photodissociation Dynamics Of Alkyl Bromides

This dissertation presents my main research work during my doctoral course. In this dissertation, we show an ion velocity map imaging system made by us and apply it to research the phtodissociation dynamics of alkyl bromides. Significant results are shown as follows:1. Ion Velocity Map Imaging System(1) The ion lens optics has been designed using a 3D ion trajectory simulation package (Simion7.0). The lens characteristics can well be simulated. The simulation got an effect that all particles with the same initial velocity vector were mapped onto the same point on the detector.(2) We measured the velocity distribution of molecular beam and dynamics properties of a standard sample. The results release that the setup's capabilities are good, the focus effects are very well and the experimental data are creditable.2. Experiment(1) We investigated the photodissociation dynamics of alkyl bromides R-Br (R= alkyl radical) (C₂H₅Br, n-C₃H₇Br, n-C₄H₉Br, n-C₅H₁₁Br, i-C₃H₇Br,) using resonance-enhanced multiphoton ionization (REMPI) with time of flight mass spectrometry (TOF-MS) at 234 and 267 nm. The branching ratios N(Br^*)/N(Br) of compounds at two wavelengths were measured and some detailed information concerning the photodissociation process was discussed.(2) The photodissociation dynamics of the CCl₃Br was studied at 267 nm. The there-dimensional velocity and angular distributions of Br(²P_3/2) and Br^*(²P_1/2) were determined. The values of anisotropy parameterβwereβ(Br)=-0.48 andβ(Br^*)=1.44, respectively.