Radio-frequency plasma jet generator of singlet delta oxygen with high yield

Abstract

O 2 (a 1 Δ g ) was generated in a flowing discharge of a radio-frequency (rf) hollow electrode. The radio frequency was 99.9 MHz and the rf power was 200 W. The discharge was done in the gas mixture O2:N2:NO=200:20:10 sccm and then it was chilled reactively by the mixture Ar:NO2=200:10 sccm. The O2(a 1Δg) relative yield of 32% was achieved at the pressure of 0.43 Torr. Usage of the mixtures O2:NO=200:100 sccm and Ar:NO2=100:100 sccm resulted in the O2(a 1Δg) yield of 25% at the pressure of 0.6–0.9 Torr. The effluent was mixed with molecular iodine in a far afterglow region and it was tested in an oxygen–iodine laser. The iodine flow rate was 0.3 mmol/min. A strong enhancement of atomic iodine spontaneous emission at the wavelength of 1315 nm was observed in the optical resonator.

On the influence of singlet oxygen molecules on the speed of flame propagation in methane–air mixture

“…Note that the problem of generation of a large proportion of singlet delta oxygen (up to 20-25%) in an electric discharge was widely investigated during past decades in regarding with creating the oxygen-iodine laser with electric discharge pumping. Various types of electric discharge were proposed to produce a significant amount of O 2 (a 1 D g ) molecules [21][22][23]. Due to electronic-electronic (E-E) exchange…”

O 2 ( Δ 1 ) production in He∕O2 mixtures in flowing low pressure plasmas

“…Inert gas diluents and molecular additives have also been used with success by Schmiedberger with a hollow cathode radio frequency (rf) jet discharge. 12 At 0.43 Torr, a 0.32 yield was obtained by flowing an O 2 /N 2 / NO mixture through the discharge jet and then chilling the gas by mixing with a cold Ar/ NO 2 stream. However, the pressure was lower than typical high power COIL system pressures.…”

“…8,9 Current research in gas phase O 2 ͑ 1 ⌬͒ generation involves capacitive, inductive, and microwave self-sustaining electric discharges in pure O 2 and in mixtures with diluents such as N 2 and He, and e-beam non-self-sustained discharges in similar mixtures. [10][11][12][13][14][15][16] The threshold ͓O 2 ͑ 1 ⌬͔͒ / ͓O 2 ͑ 3 ⌺͔͒ ratio required for positive laser gain for conventional systems depends on the cavity temperature and can be derived from the equilibrium of the forward and reverse rates of the pumping reaction, …”

Recent advances in the development of discharge‐pumped oxygen‐iodine lasers

“…In the first series of experiments, RF plasma jets were formed using a hollow electrode structure [58,59]. Direct excitation of O and the downstream mixing of O with the products from He/NO discharges were examined.…”