Mechanisms of the formation of electron-excited molecule distributions by vibrational-rotational levels in a gas discharge

A combination of radiation and linear absorption methods is used to study the distribution of molecules by rotational levels in the ground and excited electron states. The energy distributions of the radicals OH and CH and stable molecules N2 and CO in a glow-discharge plasma are examined; two groups of rotationally excited molecules are identified in excited electron states of OH, and the mechanisms of the formation of these two groups are established. A method is then proposed for determining the neutral gas temperature of a nonequilibrium plasma from the emission spectra of the OH radical and the N2 molecule. A model is also presented which accounts for the anomalous alternation of intensities in the spectrum of the 2+ system of N2.