For the first time the emission of the radiative dissociation continuum of the hydrogen molecule ($a^{ 3}\Sigma_{ g}^{ +} \to b^{ 3}\Sigma_{ u}^{ +}$ electronic transition) is proposed to be used as a source of information for the spectroscopic diagnostics of non-equilibrium plasmas. The detailed analysis of excitation-deactivation kinetics, rate constants of various collisional and radiative transitions and fitting procedures made it possible to develop two new methods of diagnostics of: (1) the ground $X^{ 1}\Sigma_{ g}^{ +}$ state vibrational temperature $T_{ \text{ vib}}$ from the relative intensity distribution, and (2) the rate of electron impact dissociation $(d[\mbox{ H$_{ 2}$}]/dt)_{ \text{ diss}}$ from the absolute intensity of the continuum. A known method of determination of $T_{ \text{ vib}}$ from relative intensities of Fulcher-$\alpha$ bands was seriously corrected and simplified due to the revision of $d \to a$ transition probabilities and cross sections of $d \gets X$ electron impact excitation. General considerations are illustrated with examples of experiments in pure hydrogen capillary-arc and H$_{ 2}$+Ar microwave discharges.
Categories: physics.plasm-ph