Issue 0, 1980

Reactions forming electronically-excited free radicals. Part 2.—Formation of N4S, N 2D and N 2P atoms in the H + NF2 reaction, and N atom reactions

Abstract

The kinetics of reactions (at 298 K) involving ground-state N 4S and excited-state N 2D, 2P atoms have been studied using resonance-fluorescence detection in a discharge-flow system. The N 4S+ NO reaction has been studied as a reference reaction: N 4S+ NO [graphic omitted] N2+ O; k1=(3.4 ± 0.3)× 10–11 cm3 molecule–1 s–1(1σ). Also, the rate constant k2 for the N 4S+ NF2 reaction has been determined: N 4S+ NF2 [graphic omitted] 2 NF; k2=(4.6 ± 0.3)× 10–12 cm3 molecule–1 s–1(1σ). The reaction H 2S+ NF2 gives NF radicals in the a1Δ state with a branching ratio [gt-or-equal]0.9: H 2S+ NF2→ NF a1Δ+ HF X1+. This conclusion is drawn from a study of concentration profiles of N 4S and N 2D atoms in the state-selective reactions (4a), (4b): H 2S+ NF a1Δ→ N 2D+ HF X1+(4a), H 2S+ NF X3→ N 4S+ HF X1+.(4b)., Although N 2D atoms are an initial product of the H + NF reaction. N 4S atoms are formed only at longer reaction times when [N 2D] has mostly decayed. Thus, it is inferred that NF X3 is not a major initial product of the H + NF2 reaction.

Chemiluminescence is emitted in the H + NF2 reaction from excited NF a1Δ, b1+ and from excited N2B3Πg and N2a1Πg in the First Positive (B–A) and Lyman–Birge–Hopfield (a–X) band systems. The precursor of NH chemiluminescence in the H + NF2 system is thought to be ground-state NH X3 formed in the reaction N 2D+ H2→ NH X3+ H.

Article information

Article type
Paper

J. Chem. Soc., Faraday Trans. 2, 1980,76, 1543-1560

Reactions forming electronically-excited free radicals. Part 2.—Formation of N4S, N 2D and N 2P atoms in the H + NF2 reaction, and N atom reactions

C. T. Cheah and M. A. A. Clyne, J. Chem. Soc., Faraday Trans. 2, 1980, 76, 1543 DOI: 10.1039/F29807601543

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