Slow-electron Velocity-map Imaging Study Of Photoionization Of P-bromofluorobenzene In The S₁ State

In this thesis,we have constructed a high resolution time-of-flight mass spectrometer?TOFMS?-slow electron velocity-map imaging?SEVI?instrument.Photoionization of excited state of p-bromofluorobenzene?p-BrFPh?has been studied in combination of resonance-enhanced multiphoton ionization?REMPI?and slow electron velocity-map imaging methods with the aid of high-level quantum chemical calculations.The S₁ state REMPI spectra and D₀ state SEVI spectra of p-BrFPh have been acquired and accurate vibrational frequencies have been assigned,in conjunction with density functional theory?DFT?calculations.The controversially vibrational frequencies in the REMPI spectrum have been reassigned and the excitation energies of S₁ state is deduced as 36246±4 cm-1.It is the first time to report the assignment of SEVI spectra and adiabatic ionization energies of D₀ state?72405±8 cm-1?.In SEVI technique,photoelectron angular distribution of p-BrFPh have been extracted and the variation of anisotropy parameters of D₀O⁰ state with photoelectron kinetic energy has been investigated.The shape resonance in the near-threshold ionization of p-BrFPh has been revealed.