Dissociation and excitation coefficients of nitrogen molecules and radical generation in nitrogen plasma

• The dissociation and excitation coefficients of nitrogen molecules.
• Hydroxyl generation from nitrogen gas.
• Nitrogen monoxide generation from nitrogen gas.

The dissociation and excitation coefficients of nitrogen molecules are investigated by making use of the Boltzmann distribution of the electrons in atmospheric plasma. The excitation and electron-impact dissociation coefficients are analytically expressed in terms of the electron temperature Te in units of eV. As an application example of these coefficients, hydroxyl generation through nitrogen plasma jet is investigated, showing that the hydroxyl concentration nOH increases, reaches its peak value and then deceases, as the mole fraction χ of water molecules increases from zero to a few percents. The experimental data of the hydroxyl generation agree qualitatively with analytical results obtained from a theoretical model, confirming that a nitrogen plasma jet is one of the best means of hydroxyl production. The other example of the coefficient application is the nitrogen monoxide generation by making use of microwave energy at 2.45 GHz. The nitrogen monoxide concentration can easily be controlled by the nitrogen flow rate, the mole fraction of the oxygen gas, and the microwave power. An experiment involving nitrogen monoxide production was conducted, and the experimental data were found to agree remarkably well with the theoretical results from the analytical expression.