Measurement of the Ar(1s_y) state densities by two OES methods in Ar–N₂ discharges

In this work, results from two methods for the determination of the Ar(1s_y) densities are compared in an Ar–N₂ discharge. These methods involve measurements of optical emission spectroscopy (OES). The first method (band method) uses the bands belonging to the N₂(C → B) second positive system, while the second method (branching fraction method) uses the line intensities corresponding to the Ar(2p_x → 1s_y) transitions. These techniques were tested in the negative glow of dc discharge and the results show remarkable agreement. (paper)