Mass Analyzed Threshold Ionization Spectra Of Two Anisole Derivatives

High resolution Zero Kinetic Energy?ZEKE?spectroscopy is one of the highest resolution spectrum technologies to study the characteristics of energy states above the ionization threshold of atoms and molecules.It is of great significance for insight into the internal information of atoms and molecules,and study the interaction of atoms,molecules and photons.Benzene derivative are important organic molecules,these are crucial research model of photophysical chemistry,which play an important role in the study of atomic and molecular physics,biomedicine,astrophysics and other fields.In this thesis,we base on 4-ethylanisole and 4-isopropylanisole as the research objects and take advantage of the Resonance-enhanced Multiphoton Ionization?REMPI?spectroscopy and Mass-analyzed Threshold Ionization?MATI?spectroscopy.In combination with the Gaussian 09 calculation software to optimize the molecular geometry and calculate the vibration frequency and energy,we studied the vibration spectra of the two molecules in the first excited state S1 and cationic ground state D₀.Their accurate adiabatic ionization energy and molecular vibronic characteristics are obtained.We firstly reported the one-color resonant two-photon ionization?1CR2PI?and MATI spectra of 4-ethylanisole.And the band origin of S₁?S₀ transition and accurate adiabatic ionization energy of 4-ethylanisole are determined to be 35 575 ± 2 cm^-1 and 63 718 ± 5 cm^-1,respectively.Through the theoretical calculation,the Franck-Condon simulation of the vibrationally resolved electronic spectra for D₀ ? S₁ transition is calculated.The simulation results are very important for the assignment of the vibronic peaks in MATI spectrum.We reported the 1C-R2 PI spectra,ultraviolet-ultraviolet hole-burning?UV-UV HB?and MATI spectra of 4-isopropylanisole,and firstly proved that there are only two rotamers?cis and trans?of 4-isopropylanisole.The excitation energies of cis and trans rotational isomers of S₁ ? S₀ transition aredetermined to be 35 628 ± 2 cm^-1 and 35 679 ± 2 cm^-1,respectively.And their adiabatic ionization energies are determined as 63 456 ± 5 cm^-1 and 63 508 ± 5 cm^-1,respectively.