Slow Electron Velocity-map Imaging Study On Photo-ionization Of Excited State Of O-chlorofluorobenzene

In this thesis,we investigate the excited state and ionic state of o-Chlorofluorobenzene by using the theresonance-enhanced multiphoton ionization technique(REMPI),slow electron velocity-map imaging(SEVI)methods and high-level theoretical calculations.Based on one-color resonant two-photon ionization and time of flight mass spectrometry,we obtained the REMPI spectrum for S1 state;Using SEVI technique,we obtained the SEVI spectra for D0 state.The adiabatic excitation energy(37059±4cm-1)and adiabatic ionization energy(70979±8cm-1)of o-ClFPh have been acquired.We used high-level theoretical calculation to analyze the geometry and vibrational frequencies of o-ClFPh molecules.The theoretical calculation are in good agreement with the experimental observations.The vibrational structure of the S1 state of o-C1FPh was observed from the REMPI spectrum,and the vibrational structure of the D0 state was obtained from the SEVI spectrum.The electronic vibration transition of o-ClFPh were assigned for the first time.Franck-Condon simulations of REMPI and SEVI spectrum for o-ClFPh were performed.We discussed the vibration mixing effect(Duschinsky effect)of the o-ClFPh.Using SEVI technique,photoelectron angular distribution of o-C1FPh have been extracted and the variation of anisotropy parameters of D0 00 state with photoelectron kinetic energy has been investigated.The shape resonance in the near-threshold ionization of o-ClFPh has been revealed.