Cacuum ultraviolet photolysis of ethyl bromide at 106.7-104.8nm

Abstract

Vacuum ultraviolet photolysis of ethyl bromide was performed at 106.7 - 104.8 nm (11.4 - 11.6 eV) in the pressure range 0.2 - 20 Torr using an Argon resonance lamp. Since the photon energy is higher than the ionization potential of ethyl bromide, 50\% of absorbed light leads to ions. Principal reaction products, $C_2H_4,\; C_2H_6,\; C_2H_2,\; CH_4$, and $C_3H_8$, were identified. Product distributions were obtained with various pressures and the pressure effect was studied. As a radical scavenger, No gas was used and the scavenger effect was also studied. As a major primary photochemical decomposition process, molecular elimination of HBr and ethylene formation was suggested and pressure dependence was also observed. In the decomposition of vrbrationally excited ethylene to acetylent, the ratio of collisional stabilization to decomposition increased with increasing pressure. The decomposition process was interpreted in view of the short-lived Rydberg transitions due to the high photon energy of the irradiated beams.