Gas phase photolysis of ethyl bromide at 123.6 nm

Abstract

A vacuum ultra-violet photolysis of ethyl bromide was studied in the pressure range of 0.5 - 19.9 Torr and at 123.6 nm Krypton resonance line. The pressure effect by adding an inert gas, i.e., He, was also observed. In the observation the monatomic gas is found to be no effect in the reaction. A scavenger effect of the reaction was performed by adding a radical scavenger No gas and was found to be quite efficient to scavenge a radical product $C_2H_6$. The observation showed $C_2H_4$ as a major reaction product and which was interpreted in terms of a molecular elimination. Nontheless $\phi{C}_2H_4/\phi{C}_2H_6$ decreased with pressure increase. This observation may be attributed by the existance of two electronically excited states. One proceeds to the molecular elimination and other to carbon-bromine bond fission. The excitation and the decomposition mechanisms between two excited states and the reaction products were interpreted in terms of the first excitation which proceeds the molecular elimination, and the second excitation which resulted from the first excitation state by collisional cross over decomposes by carbon-bromine bond fission.