Reactions of N(22D) with Alkane Hydrocarbons to Produce NH(X  3Σ−)

Ground state NH radicals could be detected as products of the reactions of N(22D) with simple alkane hydrocarbons. N(2D) was produced by two-photon dissociation of NO, while NH (X 3Σ−) was detected by laser-induced fluorescence. The nascent vibrational population ratio, NH(v″ = 1)/NH(v″ = 0), was determined to be 0.6, 0.5, 0.5, and 0.5 for CH4, C2H6, C3H8, and C(CH3)4, respectively. These ratios are smaller than that for H2, 0.8, but much larger than the prior ones. The nascent rotational state distributions of NH(X 3Σ−, v″ = 0) were determined for CH4, C2H6, and C3H8. The distributions were much hotter than the prior ones and showed little dependence on the complexity of the hydrocarbons. This suggests that the intermediate complexes which lead to the production of NH are short-lived and decompose before intramolecular vibrational redistribution (ivr). The yields for the production of NH(v″ = 0) for heavy alkanes were smaller than that for CH4. There must be exit channels other than NH production, such as C–C bond cleavage processes.