Rotational and vibrational temperatures of molecular hydrogen in a hollow cathode glow discharge

Abstract

Optical emission spectroscopy is used for the determination of hydrogen molecule rotational Trot and vibrational Tvib and translational temperature Ttr. The experiment was carried out using copper or titanium hollow cathode discharges operated in pure hydrogen. The rotational temperature of excited electron energy levels is determined from Fulcher-α diagonal bands ( electronic transition, P-, Q- and R-branches), which were later used to derive the rovibronic temperature of the hydrogen molecule ground state, which is assumed equal to Ttr. The vibrational temperature Tvib is determined for the same electronic transition (Q-branch with ν′ = 2,3; Δν = 0). For all temperatures the radial temperature distribution is reported.