C2 creation,emission, and laser-induced fluorescence in flames and cold gases

We describe photochemical production of C₂ in the upper (d³_g) and the lower (a³_u) levels of the Swan-band transitions by 266 and 292-nm laser irradiation of flames and room-temperature flows of acetylene and ethylene. Topics treated include the spectroscopy of the Swan bands, lifetimes and quenching of the Swan-band emission, intensity dependences of the Swan-band emission in several environments, profiles of C₂ in low-pressure hydrocarbon flames, and the affect of Swan-band emission on three-photon-excited fluorescence detection of atomic hydrogen in hydrocarbon flames.This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences