Role of excimer formation and induced photoemission on the Ar metastable kinetics in atmospheric pressure Ar–NH₃ dielectric barrier discharges

Abstract Tunable diode laser absorption spectroscopy was used to record the space-and time-resolved number density of argon metastable atoms, Ar(1s 3 ) (Paschen notation), in plane-to-plane dielectric barrier discharges (DBDs) operated a Penning Ar–NH mixture at atmospheric pressure. In both low-frequency (LF 650 V, 50 kHz) and dual LF–radiofrequency (RF 190 5 MHz) α – γ mode, revealed single peak per half-period LF voltage, with rise decay times sub-microsecond time scale. These results were compared predictions 1D fluid model based on continuity momentum equations for electrons, ions (Ar + Ar 2 excited 1s atoms as well electron energy balance equation. Using scheme commonly reported Ar-based DBDs homogeneous regime, kinetics exhibited much slower than ones seen experiments. The improved by considering fast creation * excimers through three-body reactions involving Ar(1s) rapid loss vacuum ultraviolet light emission. optically thin media such photons, they can readily reach barriers DBD electrodes induce secondary It is shown that photoemission play significant role not only kinetics, but also dominant ionization pathways possible transition frequency RF–LF discharges.