Absolute Concentration of OH Radicals in Atmospheric Pressure Glow Discharges with a Liquid Electrode Measured by Laser-Induced Fluorescence Spectroscopy

The OH radical density and gas temperature in atmospheric pressure glow discharges with a liquid cathode or anode is measured with a laser-induced fluorescence (LIF) technique exciting the P(2)(3), Q(1)(4), and Q(1)(9) branches of the X(2)Pi, nu '' = 0-A(2) Sigma, nu' = 3 transition. Glow discharge in contact with liquid is generated by positive and negative voltages at currents of 10-28.5 mA. The density of OH radicals linearly increases from 1.32 x 10(21) (water anode) and 1.3 x 10(21) m(-3) (water cathode) to 8.95 x 10(21) and 1.78 x 10(22) m(-3), respectively, with the increase of the discharge current from 10 to 28.5 mA. (C) 2011 The Japan Society of Applied Physics