“…In addition, people are short of the cross section data for nitrogen, especially the impact excitation and emission cross sections [7] . Therefore, most of the theoretical investigations mainly focus on simulations of certain characteristic lines, which aim at the explanation of the experimental measurements [3,7,9] although experimental studies on the OES in nitrogen plasma are rather common. More importantly, to author's knowledge, no theoretical investigations on the OES, in a point of view of plasma process mechanisms and the connection between the spectrum and the micro-quantities using any model, have been reported yet.…”