Diode Laser Absorption Spectroscopy And Calculation For The Vibrational Spectroscopy Constants Of O₂～-

Due to low amplitude fluctuation and excellent frequency and amplitude modulation capability, diode lasers have been excellent light sources for investigating absorption spectra of atoms and molecules especially in the wavelength region of the near infrared, which coincides with most atomic and molecular transitions.In this paper, a diode laser spectroscopy measurement system was demonstrated, which combined some highly sensitive spectroscopic techniques. It can be used for detection of transient molecules spectra.Based on this system, spectral lines of N₂ excited states transition were obtained in the Optical Heterodyne Concentration Modulation Spectroscopy experiment. In addition, the line shapes of spectral signal under different demodulated phases were measured and analyzed. Spectral lines of N₂⁺or N₂ excited states transition were observed in the Auto-Balanced Differential Velocity Spectroscopy experiment or Auto-Balanced Differential Concentration Spectroscopy experiment, respectively. The experimental parameters were studied in the two experiments, too.Oxygen negative ion is one of the most important and special ions in the lower ionosphere. It was studied theoretically in this paper. Firstly, the turning points of X²Π_g and A²Π_u potential curves were calculated in the RKR programme. Secondly, the origin bands and Franck-Condon factors in the A²Π_u -X²Π_g transitions were obtained in the LEVEL programme. The results were very useful for the further study of oxygen negative ion.