Production of molecules on a surface under plasma exposure: example of NO on pyrex

We propose a new experimental approach to the study of surface-catalysed nitric oxide production under plasma exposure. Stable nitrogen species are grafted to the surface of a pyrex discharge tube during N2 plasma pretreatment. These species are trapped by surface active sites and on being exposed to O2 plasma, they initiate the production of NO molecules, which are detected using tunable diode laser absorption spectroscopy. Supposing that nitrogen species are adsorbed N atoms, we estimate the initial surface coverage as [Nads] = 3 ? 1013?cm?2. This gives an assessment of the lower boundary of the density of surface active sites.