Development Of Laser Photoionization Time Mass Spectrometry And Photoelectron Velocity Imaging Spectrometer

Time-of-flight mass spectrometry and photoelectron velocity imaging technology are one of the main methods to study the atomic and molecular photoionization dynamics.Based on the previous research,we designed and built a new set of laser photoionization time-of-flight mass spectrometer and photoelectron velocity imaging spectrometer.The main improvement is that the research system extends from stable molecules to active molecules,such as free radicals;Carrying out high-resolution photoelectron velocity imaging research;combining femtosecond laser and photoelectron velocity imaging to study the non-adiabatic dynamics of the excited state of free radicals.This article introduces the development of pyrolysis generation equipment,the development and debugging of time-of-flight mass spectrometry instruments,and the preliminary design of optoelectronic imaging spectrometer.Resonance-enhanced multiphoton ionization experiments around the S₁ state of styrene molecules were commissioned to optimize the resolution of time-of-flight mass spectrometry and REMPI spectrometers.The mass spectrometry resolution reached 260,and the full width at half maximum height of the REMPI spectrum peak was?E=3.81 cm^-1.Using monochromatic resonance two-photon ionization?1C-R2PI?technology to study the excited state spectrum of p-methylanisole,combined with high-precision quantitative calculation,the ground state and excitation of p-methylanisole were obtained.The geometric configuration of the state and the ionic state can be obtained by assigning the spectral lines to obtain the vibration sequence of the excited state and the vibration level structure information of the p-tolyl cation.The experimentally measured transition excitation energy of p-methylanisole(35424±4 cm^-1).Using the photoionization efficiency technique,the ionization energy of p-methylanisole(70655±4cm^-1)was measured.