Photoionization Spectra Of Phenylacetonitrile And O-Ethoxyphenol

Spectroscopy is a science that studies the interaction between electromagnetic waves and matter,and involves physics,chemistry and other related disciplines.By studying the spectrum,we analyze the internal properties of molecules and atoms,and realize the ex-ploration and understanding of the microscopic world.This paper mainly studies the exci-tation energy,ionization energy and vibration characteristics of the excited state and ionic state of benzene derivatives molecules.Phenylacetonitrile is a very versatile basic raw material,and the monochromatic res-onance two-photon ionization spectrum of this molecule was obtained for the first time in this experiment,and the excitation energy was determined to be 37646±2 cm^-1.In the vibrational spectrum of its first electron excited state,the signal-to-noise ratio is high in the low-frequency region,the background is low,and the resolution in the high-frequency band is low.The stable configuration,energy and vibration frequency of the ground state and excited state of the molecule were calculated by density functional theory,and the Franck-Condon spectral simulation was carried out.The experimental results are in good agreement with the theoretical calculation.Combined with theoretical calculations,the vibrational spectra of the excited states of phenylacetonitrile molecules were assigned.Combined with the literature data,it was found that the length of the substituent chain in the benzene derivative increased,and the excitation energy also increased.O-ethoxyphenol is an important fine chemical,and the excited state spectra of o-ethoxyphenol were measured by 1C-R2PI technology for the first time,and the excita-tion energy was determined to be 35892±2 cm^-1.The ionic state spectrum was studied by mass-resolution threshold ionization spectroscopy,and the accurate adiabatic ionization energy was determined to be 63317±5 cm^-1.Two-color UV-UV burn-out spectroscopy was used to determine that only one stable isomer existed in the ultrasonic molecular beam of o-ethoxyphenol molecules.The molecular structures of the ground state S₀,the first electron excited state S₁ and the cationic ground state D₀ of o-ethoxyphenol were opti-mized by B3LYP/Aug-cc-pvtz,TD-B3LYP/Aug-cc-pvtz and B3LYP/Aug-cc-pvtz methods,and the vibration frequencies of each state were calculated,and the Franck-Condon spec-tral simulation was carried out.The changes of molecular structure during excitation and ionization were analyzed in detail,and it was found that the size of the aromatic ring in-creased from the ground state to the excited state,and the size of the aromatic ring in-creased from the ground state to the excited state and shrank from the excited state to the ionic ground state.These structural changes activate the vibrational modes of many aro-matic rings in the plane of the ring in both excited and ionic states.The spectra measured by the experiment are basically consistent with the Franck-Condon simulation spectrum,and combined with the Franck-Condon simulation and theoretical calculation,the vibra-tional spectra of the excited state and cationic ground state measured by the experiment are assigned.The effects of hydroxyl and ethoxy substitution on excitation energy and ionization energy were studied.These works provide important reference materials for photophysics,photochemistry and other related research.