LIF spectroscopy of OH radicals in a micro-flow DC discharge in Ar and He with a liquid electrode

The laser-induced fluorescence spectroscopy on a micro-flow discharge with water electrode is carried out in order to investigate OH radicals. The branches P2(6), P1(4) and P2(3) of X2Π, ν′′ = 0−A2Σ, ν′ = 1 transition are used. Laser-induced fluorescence is used in order to estimate the density of OH radicals and density of water vapor in a core of the plasma. Sputtering yield of H2O from the liquid electrode is calculated based on experimental data. It is revealed that plasma core consists of 8–10% of water in both Ar and He discharges. The density of OH radicals in the micro-flow He plasma is higher than in the glow discharge with liquid electrode and in Ar micro-flow discharge due to constriction of the positive column and different mechanism of the OH radical production