Abstract: Visible Chemiluminescence in the region of 380～500 nm was measured from the reaction of O( 3P ) atoms with carbon disulfide under various pressures using crossed molecular beam apparatus. The emission spectra were assigned to 3B1→ 1A1 transition of gaseous sulfur dioxide molecules. 3B1 state of sulfur dioxide is mainly composed of vibrational ground state and excited vibrational state of bending vibrational mode, vibrational band progressions in the lower state of bending modes and stretching modes were observed. The spectra under various pressures and the reaction mechanism were discussed. It was proposed that 3B1 state of sulfur dioxide was produced from multistage processes.

Key words: Crossed molecular beam, Chemiluminescence, Gas-phase reaction