Atmospheric pressure generation of O2(a1Δg) by microplasmas

The generation of singlet delta oxygen states (O-2(a(1)Delta(g))) by microplasmas has been studied experimentally. In the present paper, it is shown that micro-cathode sustained discharges (MCSD's) can be used to produce high fluxes of O-2(a(1)Delta(g)) at atmospheric pressure. In He/O-2/NO mixtures, O-2(a(1)Delta(g)) number densities higher than 10(16) cm(-3) can be generated by this 3-electrode configuration and transported over distances of some tens of cm. In fact, at total flow rates up to 30 ln/min, O-2(a(1)Delta(g)) fluxes above 10 mmol/h were measured in the MCSD afterglow, at 26 cm downstream. As a result, MCSD's appear to be very efficient and suitable tools for the continuous production of large amounts of O-2(a(1)Delta(g)) at atmospheric pressure, which could give rise to a wide range of new applications, namely biological. The effect of different parameters such as gas flows and mixtures, and discharge current are discussed in the paper.