Degenerate four wave mixing and laser induced fluorescence of pyrazine and pyridazine

Results from degenerate four wave mixing (DFWM) and laser induced fluorescence (LIF) of pyrazine and pyridazine are presented. The DFWM spectrum of pyrazine from a supersonic jet reflected faithfully the absorption probability, while the LIF spectrum was complicated by rotation-dependent intersystem crossing. The low fluorescence yield of pyridazine prohibited direct LIF measurements, but its DFWM spectrum was in good agreement with previous abasorption spectra. DFWM is an absorption based technique, so it is deal for high resolution spectroscopy studies when the upper state dynamics are unfavorable for LIF detection.