2-16. Distribution of Electron Energy Between Different Channels of Excitation and Ionization. After analyzing Figs. 2-27-2-34, identify molecular gases with the highest abil- ity to selectively localize discharge energy into vibrational excitation. What is the highest percentage of electron energy that can be selectively transferred to vibrational excitation? Which values of reduced electric field or electron temperatures are optimal to reach this selective regime? n, 100% elastic scattering Ar excitation Kr excitation no ionization n.% 80 02 60 40 20 ionization 10-5 0.1 NO H 1 10 1 (E/no)+1016, V+cm 10 Figure 2-27. Electron energy distribution between excitation channels in Kr (5%)-Ar (95%) mixture. (E/no) 1016, V cm Figure 2-28. Fraction of electron energy spent on vibrational excitation in discharges in molecular gases: O2, NO, and H2. n. % 100 rotational excitation 75H 50 25- 0.1 . % vibrational excitation 80 vibrational excitation 100 electronic excitation 001 other modes 010 (E/no) 1016, V cm Figure 2-29. Electron energy distribution between excitation channels in CO2. 10 0+1 electronic excitation 60 exp (hurt) = 0.2 exp (hurt y) = 0.5 40 20 rotational excitation ionization 10 30 (E/no) 1016, V cm Figure 2-30. Electron energy distribution between excitation channels in molecular nitrogen at different vibrational temperatures. 80 60 n.% vibrational excitation dissociative attachment elastic scattering 40 electronic excitation 20 1 3 ionization 4 Te, ev 100- n.% N vibration O2 vibration O2 electronic exc. 50- rotation elastic N electronic exc. ionization 10 Figure 2-31. Electron energy distribution between different excitation and ionization channels in water vapor. (E/no) 1016, V cm Figure 2-32. Electron energy distribution between different excitation and ionization channels in air. 7.% CO vibration electronic excitation 60 40 CO2 (001) 20 20 CO (010) CO (n00-0m0) 0 2 6 8 10 (E/no) *1016, V cm 80 60 Figure 2-34. Electron energy distribution bet- ween different excitation and ionization channels in CO. 40 20 ionization Figure 2-33. Electron energy distribution bet- ween different excitation and ionization chan- nels in CO(50%)-CO(50%) mixture. n.% vibrational excitation electronic excitation 0 4 6 8 (E/no) 1016, V* cm 10 20