Project supported by the Funds for Innovative Research Groups of China (Grant No. 51021005);the National Basic Research Program of China (Grant No. 2009CB724504);the National Natural Science Foundation of China (Grant No. 50707036)
Local electron mean energy (LEME) has a direct effect on the rates of collisional ionization of molecules and atoms by electrons. Electron-impact ionization plays an important role and is the main process for the pr...