Generation and Distribution of Fast Atomic Species(N+, Nf) in Nitrogen Glow Discharge

Using a combination of the Monte Carlo models of fast electrons, of molecular ions (N+2) and of atomic species (N+, Nf), the influence of the discharge pressure (P) and voltage (Vc) on the energy distributions of fast atomic species (N+, Nf) produced by e--N2s and N2+-N2s dissociation reactions at the cathode in a nitrogen dc glow discharge was investigated. Both the angular distributions and the density distributions along the radius of the species (N+, Nf) produced by the two dissociations at the cathode were calculated. The results show that: (1) there is an optimum discharge condition for P and Vc in order to obtain the species (N+, Nf) at the cathode with high a density and energy (2) when the voltage is above 800 V, the species (N+, Nf) bombarding the cathode are mainly produced by the N+2-N2s dissociation, whereas when the voltage is below 300 V, they are mainly produced by the e--N2s dissociation, and (3) at high voltages the incident angles of a considerable number of Nf into the cathode are quite small. The density of the species (N+, Nf) at the cathode increases with the voltage, and when the pressure goes up to about 133 Pa, it decreases with the increasing pressure