Surface recombination of oxygen atoms in O-2 plasma at increased pressure: II. Vibrational temperature and surface production of ozoneстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Ozone production in an oxygen glow discharge in a quartz tube was studied in the pressure range of 10-50 Torr. The O-3 density distribution along the tube diameter was measured by UV absorption spectroscopy, and ozone vibrational temperature T-V was found comparing the calculated ab initio absorption spectra with the experimental ones. It has been shown that the O-3 production mainly occurs on a tube surface whereas ozone is lost in the tube centre where in contrast the electron and oxygen atom densities are maximal. Two models were used to analyse the obtained results. The first one is a kinetic 1D model for the processes occurring near the tube walls with the participation of the main particles: O(P-3), O-2, O-2((1)Delta(g)) and O-3 molecules in different vibrational states. The agreement of O-3 and O(P-3) density profiles and TV calculated in the model with observed ones was reached by varying the single model parameter-ozone production probability (gamma(O3)) on the quartz tube surface on the assumption that O-3 production occurs mainly in the surface recombination of physisorbed O(P-3) and O-2. The phenomenological model of the surface processes with the participation of oxygen atoms and molecules including singlet oxygen molecules was also considered to analyse gamma(O3) data obtained in the kinetic model. A good agreement between the experimental data and the data of both models-the kinetic 1D model and the phenomenological surface model-was obtained in the full range of the studied conditions that allowed consideration of the ozone surface production mechanism in more detail. The important role of singlet oxygen in ozone surface production was shown. The O-3 surface production rate directly depends on the density of physisorbed oxygen atoms and molecules and can be high with increasing pressure and energy inputted into plasma while simultaneously keeping the surface temperature low enough. Using the special discharge cell design, such an approach opens up the possibility to develop compact ozonizers having high ozone yield at the low energy cost of O -> O-3 conversion.