The paper is the third of three papers on the kinetics of particle-beam-generated molecular plasmas. The author completes the kinetic investigation by an analysis of the Boltzmann low- and medium-energy equation available for any stationary particle-beam-generated molecular (or atomic) plasma, including all inelastic processes. Use of this analysis together with the moment conservation equations provides a means to obtain analytically the electron density and 'temperature' in the plasma. Theoretical results are compared with experimental parameters measured in O₂ by Pointu and Zeller (1986) Orsay, with gun jet electrons, and orders of magnitude are in good agreement when diffusion is taken into account.