Active Species in R (He,Ne,Ar)-Molecular Gas Plasmas

Abstract

In high pressure \(\mathrm{He}\) glow discharges, the 3 - body reactions of \(\mathrm{He}\left(2^{3} \mathrm{~S}\right)\) metastable atoms and \(\mathrm{He}^{+}\)ions with \(\mathrm{He}\) and \(\mathrm{N}_{2}\) are in competition to excite the \(\mathrm{N}_{2}^{+}(\mathrm{B}, 0)\) radiative states. With \(\left[\mathrm{He}^{+}\right]<10^{10} \mathrm{~cm}^{-3}\) and \(\left[\mathrm{He}\left(2^{3} \mathrm{~S}\right)\right] \sim 10^{12} \mathrm{~cm}^{3}\) as found in a DC glow discharge, it is estimated that the 3-body reaction \(\operatorname{He}\left(2^{3} \mathrm{~S}\right)+\) \(\mathrm{He}+\mathrm{N}_{2}\) was the dominant process. By using the actinometry method with \(\mathrm{Ar}\) and \(\mathrm{Ne}\) impurity in \(\mathrm{N}_{2}-\mathrm{H}_{2} \mathrm{DC}\) glow discharge at 5 Torr, it was found in the negative glow of the DC discharge a small increase of all \(\mathrm{N}_{2}\) vibrational states and cathode temperatures as a few \(\mathrm{H}_{2}\) was introduced into \(\mathrm{N}_{2}\). Finally, it is discussed the methods to obtain the plasma gas temperatures from the rotational structures of \(\mathrm{N}_{2}, \mathrm{CN}, \mathrm{OH}, \mathrm{H}_{2}\) and \(\mathrm{O}_{2}\) radiative states.