The Origin of SO2 Afterglows as Revealed by Magnetic Field Effects

The chemiluminescence intensity in the low pressure diffusion flame of the CS 2 + O/N 2 system wasfound to be considerably affected by external magnetic fields. The emitter in the flame was identifiedas the main emitter in the SO 2 afterglow. The measurements of the field strength dependence, collisionaleffect, and spectral distribution of the magnetic field effect revealed the major emitter as the SO 2 in the C ˜ state. External magnetic fields were also found to quench fluorescence remarkably emitted from thevibronic levels just below the predissociation threshold in the C ˜ state. From the observed vibrational-level,field-strength, and pressure dependences of the magnetic quenching, it became evident that the majoremitter of chemiluminescence in the flame could be assigned to the SO 2 molecule in the vibronic levelslocated at about 800 cm –1 below the predissociation threshold in the C ˜ state