Rate Constants, Branching Ratios, and Energy Disposal for Nf(b,a,X) and HF(v) Formation from the H + NF2 Reaction

Article abstract of DOI:10.1021/j150610a015

The rate constant and energy disposal for the H + NF2 reaction has been measured by observing infrared and visible chemiluminescence in a fast-flow, low concentration, flowing-afterglow apparatus at room temperature.The rate constant was determined by comparing the HF(v) emission intensity to the HCl(v) emission intensity from the H + Cl2 reaction.The rate constant for formation of HF(v >=1) is 3.8 x 1E-12 cm³ molecule ^-1 s^-1.Allowance for HF(v=0) formation gives a total rate constant which is about a factor of 3 larger.The observed HF(v₁, v₂, v₃, v₄) distribution is0.75: 0.20: 0.04: 0.01.The NF(a¹Δ-X³Σ^-) emission also was observed; the NF(a¹Δ) vibrational distribution is v₀:v₁:v₂ = 0.73:0.19:0.08.Comparison of the NF(b¹Σ⁺) and NF(a¹Δ) emission intensities and using the HF(v = 4) emission, which is energetically allowed only for formation of NF(X³Σ^-), gave NF(X):NF(a):NF(b) branching fractions of 0.07:0.91:0.02.By comparing the NF(a¹Δ-X³Σ^-) intensity from H + NF2 to the HF(3-0) emission intensity from the H + ClF reaction and by using the known rate constant and energy disposal for H + ClF, the radiative lifetime of NF(a¹Δ) was determined to be 5.6 s.The 0-0, 1-1, and 2-2 band wavelengths of the NF(a¹Δ-X³Σ^-) transition yielded ο_e' = 1184 cm^-1 and ο_e'ξ_e' = 8.5 cm ^-1.