Experimental And Theoretical Kinetics Studies Of Dissociative Photoionization Of L-menthone

In this dissertation, the dissociative photoionization of L-menthone has been investigated with photoionization mass spectrometry using a synchrotron radiation source, and quantum chemical theory.In the first chapter, the definition of aerosol and the source and classification of secondary organic aerosols are briefly introduced firstly. Some biogenic volatile organic compounds (BVOCs) and their oxidation mechanisms are described. Then, the basic conceptions on photoionization and photodissociation, such as adiabatic ionization energy, vertical ionization energy, apperance energy, and the fundamental phtotodissociation mechanism are discussed. Finally, the common experimental method and theoretical methods are also introduced.In the second chapter, the development, characteristics and applications of synchrotron radiation are summarized at first, and the parameters of storage ring of National Synchrotron Radiation Laboratory (NRSL) are also introduced. Then, it introduces the structure and equipments of atomic and molecular physics beamline and endstation. The undulator can provide the tunable VUV synchrotron radiation in the energy range of 7.5-124 eV. Secondly, the formation mechanism of ultrasonic molecular beam and the principle of time of flight mass spectrometer are presented briefly. Finally, the installation and testing of the gas filter system are discussed in details.In the third chapter, the theoretical foundation of quantum chemistry calculation is described brifly, and the calculation methods and basis sets used in this study are also introduced.In the forth chapter, the dissociative photoionization of L-menthone in a region～15.5 eV has been investigated with photoionization mass spectrometry using a synchrotron radiation source. The ionization energy (IE) of L-menthone and the appearance energies (AE) of its major fragment ions C₉H₁₅O⁺, C₉H₁₇⁺, C₈H₁₆⁺, C₇H₁₁O⁺, C₆H₁₀O⁺, C₆H₉O⁺, C₅H₈O⁺, C₅H₁₀⁺, C₄H₆O⁺, C₅H₉⁺, C₄H₈⁺, C₄H₇⁺, C₃H₇⁺, C₃H₆⁺, C₂H₂O⁺, and CH₃⁺ are determined with their photoionization efficiency (PIE) spectra in the photon energy region of ⁸-15.5 eV. Relative branching ratios as a function of photon energy were determined. Dissociative photoionization channels for formation of these fragment ions are proposed based on comparison of determined experimental appearance energies and energies predicted with the DFT calculations. According to our results, the experimental dissociation energies are in fair agreement with the theoretical values of the possible photodissociation channels of C₁₀H₁₈O.In the fifth chapter, the basic principle of infrared spectrum and the structure of IR/FIR beamline and endstation are firstly introduced. Then, the operating principle of FTIR is described. Finally, the infrared spectrum of some BVOCs is described in the range of 400-3500 cm^-1, experimentally and theoretically.