Measurement of O(1D) formation during thermal decomposition of CO2 behind shock waves

Abstract

Atomic Resonance Absorption Spectroscopy (ARAS) was applied to measure the time dependent concentration of electronically excited O(1D)-atoms during the thermal decomposition of CO2 behind reflected shock waves. The experiments were performed in the temperature range 4102 K≤T≤6375 K at pressures 0.2 to 1.9 bar with initial gas mixtures of 100 to 1000 ppm CO2 diluted in Ar. The measured O(1D)-formation rate at early reaction times divided by the initial reactant concentrations was found to obey the Arrhenius law: $$\begin{gathered} \left. {\frac{{d{{\left[ {O\left( {^1 D} \right)} \right]} \mathord{\left/ {\vphantom {{\left[ {O\left( {^1 D} \right)} \right]} {dt}}} \right. \kern-\nulldelimiterspace} {dt}}}}{{\left[ {CO_2 } \right]_0 \left[ {Ar} \right]}}} \right|_{t \approx 0} \hfill \\ = 1.23 \times 10^{14} \exp \left( { - 74810{K \mathord{\left/ {\vphantom {K T}} \right. \kern-\nulldelimiterspace} T}} \right)cm^3 mol^{ - 1} s^{ - 1} \hfill \\ \end{gathered} $$