Study of Collisions between Low-Energy N+ and N2: Reaction Cross Sections, Isotopic Compositions, and Kinetic Energies of the Products

Abstract

Reactive collisions between N⁺ and N₂ have been studied, and cross sections for the production of ${\mathrm{N}}_2^{+}$ have been measured for initial kinetic energies, E_{c. m.}, in the center-of-mass system between 1 and 70 eV. The kinetic energies of the product ${\mathrm{N}}_2^{+}$ have been determined. Isotopically labeled reactants were used, and the cross sections for producing ${\mathrm{N}}_2^{+}$ containing different combinations of isotopes have been measured. The reaction $${\mathrm{N}}^{+}+{\mathrm{N}}_2\to {\mathrm{N}}_2^{+}+\mathrm{N}$$ is found to proceed by both atom and electron transfer. For E_{c. m.} $\text{≲ 11\hspace{0.17em}}\mathrm{eV}$ , the cross sections for electron and atom transfer are roughly equal, but at higher E_{c. m.} the atom transfer cross section is considerably smaller than the electron transfer cross section. The kinetic energy −Q transferred into internal energy of the products is considerably larger than the minimum required for Reaction (1) to proceed. For the electron transfer process, the values determined for −Q are between 3 and 9.8 eV. The values of −Q found for the processes associated with atom transfer are between 3 and 50 eV. For E_{c. m.} $\text{≳ 24\hspace{0.17em}}\mathrm{eV}$ , it appears that a free electron may be produced by ${\mathrm{N}}^{+}+{\mathrm{N}}_2\to {\mathrm{N}}_2^{+}+{\mathrm{N}}^{+}\mathrm{+e}$ . A model for the reactions occurring in collisions between N⁺ and N₂ is developed and shown to be in qualitative agreement with the observations.