Atomic Oxygen Production and Exploration of Reaction Mechanisms in a He‐O2 Atmospheric Pressure Glow Discharge Torch

Summary: This article reports on the performance of a miniature APGD‐t conceived for the production of reactive species participating in bio‐applications. Two operating parameters were varied: the plasma‐forming gas flow rate (0.5–1.5 slm He) and the flow rate of O2 (0–50 sccm), which was injected downstream from the plasma‐forming zone, and which was used as a source of reactive species. The production of reactive species (O) was optimized, and the air entrainment in the plasma jet was minimized for a He gas flow rate of 1–1.5 slm and an O2/He volumetric ratio of 0.3 vol.‐%. A survey of the possible reaction pathways in the afterglow plasma jet suggests that the reactive species present in the plasma afterglow, and possibly reaching a remote substrate, are metastable He(23S), ground state O, OH, O2 (a1Δg), O2 (b1Σg+), N, N2, N and O3. APGD‐t jet impinging on a finger. magnified image APGD‐t jet impinging on a finger.