ELECTRON DECAY FOLLOWING d-c. DISCHARGE IONIZATION IN NO AND NO–Ne MIXTURES

Abstract

The time dependence of the electron density, N_e(t), and radiation temperature, T_e(t), has been measured in d-c. discharge afterglows of NO and NO–Ne mixtures. Microwave wave-guide transmission and noise-sampling techniques were used. In pure NO the experimental results were compared with those computed for a recombination–attachment controlled plasma using Gunton and Shaw's values, and good agreement was found. In the NO–Ne mixtures p(Ne) was about 20 Torr, and p(NO) was varied from 0.5 × 10⁻³ to 0.10 Torr. It was found that 1/N_e(t) was linear over extensive ranges of N_e(t) indicating two-body electron–ion recombination. The results yield [Formula: see text] and the three-body attachment coefficient K = 2.2 × 10⁻³¹ cm⁶sec⁻¹ for T_e = T_gas = 300 °K. T_e(t) decayed nonexponentially varying with p(NO) indicating that Penning ionization takes place together with other collision processes which are briefly discussed.