Experimental study of chlorine atom interaction with acetylene behind shock waves

Using atomic resonance absorption spectroscopy, we measure the temporal profiles of $\rm Cl$ atom concentration at interaction with acetylene behind shock waves. We used $\rm CCl_4$ thermal decay as the chlorine atom source. We used a $30$ ppm of $\rm CCl_4$ and $300$ ppm of $\rm C_2H_2$ in argon mixture for the experiments, at $1400$–$2300$ K and pressures of about $2$ bar. For experimental results, we determine the rate constant of the chlorine atom consumption in the $\rm Cl + C_2H_2 = C_2H + HCl$ reaction. The experimental data show essentially lower activation energy than the results of the theoretical calculations performed earlier, possibly due to the acetylene molecule vibrational energy contributing to overcoming the reaction barrier.