Atmospheric pressure generation of O(2)(a(1)) 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.