Photofragmentation laser-induced fluorescence of ozone: an in situ tool for precise mapping of ozone concentration in non-thermal plasmas

摘要： The absolute spatially resolved concentration of ozone has been determined in the near afterglow of a novel type of atmospheric multi-hollow barrier discharge using photofragmentation laser-induced fluorescence. The method consists of two steps: (i) photodissociation of O3 to O(3P) and O2(X3Σg?) with considerable vibrational excitation; (ii) predissociation laser-induced fluorescence of the molecular fragment via the O2(B 3Σu?, v′ = 0 ← X 3Σg?, v″ = 6) transition. Both processes happen during the same laser pulse, requiring the same excitation wavelength (≈248 nm). The fluorescence signal has been calibrated by infrared absorption. The method allows in situ observation before the afterglow chemistry significantly affects the O3 concentration, and is capable of revealing inhomogeneous ozone distributions in the reactor.