Falloff curves of the reaction CF3 (+M) = CF2 + F (+M)

L. SÖLTER; C. J. COBOS; E. TELLBACH; G. KNIGHT; J. TROE

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2020 vol. 124 p. 1236 - 1239

1089-5639

The thermal dissociation reaction CF3 (+Ar) → CF2 + F(+Ar) was studied in incident and reflected shock waves by monitoringUV absorption signals of the primary dissociation product CF2. CF3radicals were produced by thermal decomposition of CF3I. Accounting forsecondary reactions of F atoms, rate constants for the unimoleculardissociation were derived. Experimental parts of the falloff curves wereobtained over the ranges 1544−2106 K and 1.0 × 10−5 ≤ [Ar] ≤ 9.3 ×10−5 mol cm−3. Theoretical modeling allowed for a construction of the fullfalloff curves connecting the limiting low-pressure rate constants k0 = [Ar]2.5 × 1018 (T/2000 K)−5.1 exp (−42 450 K/T) cm3 mol−1 s−1 with thelimiting high-pressure rate constants k∞ = 1.6 × 1016 (T/2000K)−1.3 exp (−43 250 K/T) s−1 (center broadening factors of Fcent = 0.25,0.22, and 0.20 at 1500, 2000, and 2500 K, respectively, were used). Theinfluence of simplifications of falloff expressions and of limiting rate constants on the representation of experimental data isdiscussed.I.