Direct measurements of C 3 F 7 I dissociation rate constants using a shock tube ARAS technique

This work presents the first direct experimental study on the thermal unimolecular decomposition of n ‐C 3 F 7 I. Experiments were performed behind incident and reflected shock waves using the atomic resonance absorption spectroscopy (ARAS) technique on a resonant line of atomic iodine at 183.04 nm. The reaction C 3 F 7 I + Ar → C 3 F 7 + I + Ar (1) was studied at specific temperature (800–1200 K) and pressure (0.6–8.3 bar) ranges. Under experimental conditions, the obtained values of the rate constant at temperatures below 950 K are close to the high‐pressure limit; however, considering theoretical calculations, the influence of pressure on the rate constant at elevated temperatures remains noticeable. The resulting value of the experimental rate constant of reaction 1 is presented in the following Arrhenius form: urn:x-wiley:05388066:media:kin21244:kin21244-math-0001 Experimental data were found to correlate with the results of the Rice–Ramsperger–Kassel–Marcus –master equation analysis based on quantum‐chemical calculations. The following low‐ and high‐pressure limiting rate coefficients were obtained over the temperature range T = 300–3000 K: urn:x-wiley:05388066:media:kin21244:kin21244-math-0002 with the center broadening factor F c = 0.119.