NO-γ emissions from streamer discharges: direct electron impact excitation versus resonant energy transfer

It has been established that production of NO-gamma emission in pulsed corona discharges is dominated by the energy transfer from N(2)(A (3)Sigma(u)(+)) to the NO ground state NO(X (2)Pi(r)) while direct excitation by electron impact is negligible. However, recent studies suggest that the electron impact excitation plays a more important role. In this work, we report modelling results of NO-gamma emission associated with streamer discharges using two cross section data sets available in the literature. The first set was originally reported by Mojarrabi et al (1996 Phys. Rev. A 54 2977-82) and later updated by Brunger et al (2000 J. Phys. B: At. Mol. Opt. Phys. 33 809-19); the second set was published by Hayashi (1990 Nonequilibrium Processes in Partially Ionized Gases (NATO Advanced Science Institutes Series, Series B, Physics vol 220) ed M Capitelli and J N Bardsley (New York: Plenum) pp 333-40). According to the results, the role played by the electron impact excitation in the production of NO-gamma is drastically different when different cross sections are used. The results indicate that the first data set leads to better agreement with experimental measurements.