The interactions in plasma (Formula presented.) recycling are simplified by limiting the excitation of (Formula presented.) mixtures with (Formula presented.) or (Formula presented.) to rovibrations in a low-temperature glow discharge. In situ infra-red absorption spectroscopy measures rovibrational temperature trends, analysed for collisional energy transfer. With (Formula presented.), symmetric vibrations of (Formula presented.) show temperature behaviour similar to the asymmetric stretching due to the change in dominance from excitation to relaxation. Adding (Formula presented.) delays discharge onset, likely because the electronegativity of (Formula presented.) hinders electron avalanche formation. Both datasets aid in benchmarking kinetic models.
Brescia et al. (Wed,) studied this question.