Decomposition of NO2 in a glow discharge and electron impact ionization and attachment coefficients in NO2/air mixtures

Abstract

Nitrogen dioxide (NO2) has been shown to be decomposed into N2 and O2 in low-pressure glow discharges. The basic data needed to understand the decomposition process, such as the electron-impact ionization alpha /p20 and attachment coefficients eta /p20, where p20 is the gas pressure at 20 degrees C, are measured by a steady-state Townsend method for NO2/air mixtures with the fractional NO2 partial pressure K and for 50<E/p20<500 V cm-1 Torr-1 (152<E/N<1520 Td). The results show that ( alpha - eta )/p20 for K=1 (NO2) increases almost linearly with increasing E/p20. In NO2/air mixtures it increases significantly with decreasing K. The limiting E/p20, (E/p20)lim at which alpha /p20= eta /p20, is around 100 V cm- Torr-1 for NO2 and decreases monotonically to 33 V cm-1 Torr-1 for air with decreasing K. The alpha /p20 value for mixtures decreases significantly with increasing K, especially, at low E/p20. The value of eta /p20 increases with increasing K for the whole range of E/p20 values for which the present measurement has been carried out.