Studies On Multi-photon Spectrum Of Excite Electron States Of SO₂ Molecules

Using the techniques of multi-photon laser spectroscopy,the vibrational energy level structure and the transition kinetic process of the ground electronic states,the low excitation states of the first excitation band and the Rydberg state of the SO₂ molecule has been studied Experimentally and theoretically,in which the optical parameter generator and optical parameter amplifier?OPO/OPG?and dye laser pumped by Nd:YAG pulse laser are used as excitation source.The vibrational structure and transition process of the excitation states of the first excitation band of SO₂ molecule are experimentally studied with the technique of multi-photon laser induced dispersive fluorescence?LIDF?spectroscopy.It is found that the excitation efficiency of the exciting light of 579nm is obviously better than 532nm in the process of two-photon excitation,and the vibrational parameters of the X¹A₁ are obtained.Detecting the SO₂ molecule by the technique of fluorescence excitated by visible light,the optimal receiving wavelength 388.1 nm corresponding to the transition process of A³B₁?X¹A₁ were determined.Using laser induced fluorescence excitation spectroscopy technology,a richer SO₂ molecule excitation wavelength information is obtained,the spontaneous radiation lifet₀ and the collision relaxation rate constant k_Q of each excited state are determined by the fluorescence signal time resolution spectrum,and the coupling equilibrium relaxation time?c and the coupling coefficients?between the A¹A₂ state and the B¹B₁ state are obtained.In this paper,the Franck-Condon principle is used to simulate the excitation spectrum and emission spectra between the exciting states of the first excited band and the ground state,which has a good theoretical reference value for the experimental spectra of the first excitation band of SO₂ molecule.The Rydberg stateF¹A₂of the SO₂ molecule is studied experimentally with the technique of resonance enhanced multi-photon ionization?REMPI?spectroscopy for the first time.The multiple photon ionization spectra in the range of 420nm⁵40nm correspond to the Rydberg series of np?n=4,5,6?.And it is proved that the Rydberg series converge to the ground state of the.The converging potential of the Rydberg series and the quantum defect of p orbit are obtained by the method of least squares.In addition,the vibrational structure of the triplet F state was first observed.The research results and conclusions obtained in this work are of great significance to the detection of sulfur dioxide in the atmosphere and the study of molecular spectroscopy,which provide an important reference for the deep development of related work.