Diffusion and reactivity of ground-state nitrogen atoms N(<sup>4</sup>S) between 3 and 15 K: application to the hydrogen abstraction reaction from methane under non-energetic conditions - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2015

Diffusion and reactivity of ground-state nitrogen atoms N(4S) between 3 and 15 K: application to the hydrogen abstraction reaction from methane under non-energetic conditions

Résumé

We have characterized the CH4 + N(4S) reaction in solid phase, at very low temperature, under non-energetic conditions and where the CH4 and N reactants are in their ground states. A microwave-driven atomic source has been used to generate ground-state nitrogen atoms N(4S), and experiments have been carried out at temperatures as low as 3 K to reduce the mobility of the trapped species in solid phase and hence to freeze the first step of the CH4 + N reaction pathway. Leaving the formed solid sample in the dark for a while allows all trapped reactants to relax to the ground state, specifically radicals and excited species streaming from the plasma discharge. Such a method could be the only possibility of proving that the CH4 + N reaction occurs between CH4 and N reactants in their ground states without any additional energy to initiate the chemical process. The appearance of the CH3 reaction product, just by inducing the mobility of N atoms between 3 and 11 K, translates that a hydrogen abstraction reaction from methane, under non-energetic conditions, will start occurring at very low temperature. The formation of methyl radical, under these experimental conditions, is due to recombination processes N(4S)–N(4S) of ground-state nitrogen atoms without any contribution of cosmic ray particles or high-energy photons.

Domaines

Chimie

Dates et versions

hal-01480754 , version 1 (01-03-2017)

Identifiants

Citer

Sendres Nourry, Lahouari Krim. Diffusion and reactivity of ground-state nitrogen atoms N(4S) between 3 and 15 K: application to the hydrogen abstraction reaction from methane under non-energetic conditions . Monthly Notices of the Royal Astronomical Society, 2015, 450 (3), pp.2903-2914. ⟨10.1093/mnras/stv832⟩. ⟨hal-01480754⟩
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