Photosensitized Reaction between Hydrogen (2P) Atoms and Molecular Nitrogen

Abstract

The reaction between H(²P) atoms and molecular nitrogen has been studied. H(²P) atoms were produced by irradiating ground‐state H(²S) atoms, generated in a microwave discharge, with Lyman‐alpha radiation at 1216 Å (∼10¹⁴—10¹⁵ quanta sec^—1). The interaction of H(²P) atoms with N₂ produces ammonia but not hydrazine. Two alternative mechanisms of the primary reaction are proposed. The first involves transfer of electronic energy. $$\begin{array}{c}\mathrm{H}{(}^2\mathrm{P)+}{\mathrm{N}}_2{(}^1{\Sigma }^{+}\mathrm{g)\to }\mathrm{H}{(}^2\mathrm{S)+}{\mathrm{N}}_2^{*};\\ {\mathrm{N}}_2^{*}\text{→2}\mathrm{N}{(}^4\mathrm{S).}\end{array}$$ The second possibility is a chemical mechanism involving atom transfer. $$\mathrm{H}{(}^2\mathrm{P)+}{\mathrm{N}}_2{(}^1{\Sigma }^{+}\mathrm{g)\to }\mathrm{NH}{(}^3{\pi }_i\mathrm{)+}\mathrm{N}{(}^4\mathrm{S).}$$ Ammonia is formed either by reaction of N with H or by reaction of NH with H or H₂.