Absolute rate constant for the reaction of atomic hydrogen with acetylene over an extended pressure and temperature range

Abstract

The technique of flash photolysis coupled with time resolved detection of H via resonance fluorescence has been used to obtain absolute rate parameters for the reaction of atomic hydrogen with acetylene, i.e., H+C₂H₂?C₂H₃* (1); C₂H₃*+M→C₂H₃+M (2). The rate constant for the reaction is strongly pressure dependent and was measured over the pressure range 10 to 700 torr. The reaction was also studied as a function of temperature over the range 193 to 400 °K and the high pressure limit of the rate constant at each temperature was used to obtain the Arrhenius expression k₁= (9.63±0.60) ×10⁻¹² exp(−2430±30/1.987T) cm³ molecule⁻¹⋅sec⁻¹. The present results are compared with those of previous studies.